General and Comparative EndocrinologyThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

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365 records returned

The effects of farnesoic acid and 20-hydroxyecdysone on vitellogenin gene expression in the lobster, homarus americanus, and possible roles in the reproductive process.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the effect of farnesoic acid (FA) and 20-hydroxyecdysone (20E) on production of vitellogenin by hepatopancreas (HaVg1) was investigated by in vitro organ explant HaVg1 gene expression was stimulated by FA or 20E in a dose-dependent manner. A 2 fold and 2.2 fold increase in HaVg1 gene expression was observed with 4.2 muM FA and 0.7 muM 20E respectively. The stimulatory effect by either FA or 20E was observed principally during the first 90 min. Stimulation of HaVg1 gene expression by FA and 20E together is greater (3.3 fold increase) than that of either hormone alone. This stimulation was also observed within...
Source: General and Comparative Endocrinology - November 14, 2009 Category: Endocrinology Authors: Tiu SH, Chan SM, Tobe SS Tags: Gen Comp Endocrinol Source Type: journals

Fadrozole and finasteride exposure modulate sex steroid- and thyroid-related gene expression in Silurana (Xenopus) tropicalis early larval development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this study was to investigate the expression and activity of aromatase (cyp19; estrogen synthase) and 5beta-reductase (srd5beta; 5beta-dihydrotestosterone synthase) during amphibian embryogenesis. Expression and activity profiles of cyp19 and srd5beta were first established during Silurana (Xenopus) tropicalis embryogenesis from Nieuwkoop-Faber (NF) stage 2 (2-cell stage; 1 hour post-fertilization) to NF stage 46 (beginning of feeding; 72 hours post-fertilization). Exposures to fadrozole (an aromatase inhibitor; 0.5, 1.0 and 2.0 muM) and finasteride (a putative 5-reductase inhibitor; 25, 50 and 100 muM) we...
Source: General and Comparative Endocrinology - November 13, 2009 Category: Endocrinology Authors: Langlois VS, Duarte-Guterman P, Ing S, Pauli BD, Cooke GM, Trudeau VL Tags: Gen Comp Endocrinol Source Type: journals

Testosterone selectively affects aromatase and 5alpha-reductase activities in the green anole lizard brain.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Testosterone (T) and its metabolites are important in the regulation of reproductive behavior in males of a variety of vertebrate species. Aromatase converts T to estradiol and 5alpha -reductase converts T to 5alpha -dihydrotestosterone (DHT). Male green anole reproduction depends on androgens, yet 5alpha -reductase in the brain is not sexually dimorphic and does not vary with season. In contrast, aromatase activity in the male brain is increased during the breeding compared to non-breeding season, and males have higher levels than females during the breeding season. Aromatase is important for female, but not male, sex...
Source: General and Comparative Endocrinology - November 13, 2009 Category: Endocrinology Authors: Cohen RE, Wade J Tags: Gen Comp Endocrinol Source Type: journals

Sex differentiation and sex change in the protandrous black porgy, Acanthopagrus schlegeli.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Protandrous black porgy fish, Acanthopagrus schlegeli, have a striking life cycle with a male sex differentiation at the juvenile stage and male-to-female sex change at 3 years of age. We had characterized the sex differentiation and sex change in this species by the integrative approaches of histology, endocrine and molecular genetics. The fish differentiated in gonad at the age around 4-months and the gonad further developed with a bisexual gonad for almost for 3 years and sex change at 3 year of age. An antagonistic relationship in the testicular and ovarian tissues was found during the development of the gonadal ti...
Source: General and Comparative Endocrinology - November 13, 2009 Category: Endocrinology Authors: Wu GC, Tomy S, Lee MF, Lee YH, Yueh WS, Lin CJ, Lau EL, Chang CF Tags: Gen Comp Endocrinol Source Type: journals

Stem cells in the pituitary gland: a burgeoning field.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The pituitary gland represents the endocrine core of the organism, and is well-known for its cellular plasticity in order to meet the body's fluctuating hormonal demands. In the past, it has repeatedly been postulated that the pituitary harbors tissue-specific stem cells that participate in the generation of new endocrine cells during this dynamic cell remodeling, as well as during the slow but robust homeostatic turnover of the gland. However, their presence and identity remained elusive until this conundrum recently attracted renewed interest. Our discovery of a 'side population' using flow cytometry was the first st...
Source: General and Comparative Endocrinology - November 13, 2009 Category: Endocrinology Authors: Vankelecom H, Gremeaux L Tags: Gen Comp Endocrinol Source Type: journals

Ontogeny of ghrelin mRNA expression and identification of ghrelin-immunopositive cells in the gastrointestinal tract of the Peking duck, Anas platyrhychos.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ghrelin is an acylated peptide and an endogenous ligand for the growth hormone secretagogue receptor (GHS-R), and stimulates growth hormone release and food intake in mammals. Peking duck is a very fast growing species of poultry. Although the sequence and structure of ghrelin have recently been determined, the expression of ghrelin in Peking duck has not been studied. Here, we investigated the tissue expression and distribution of ghrelin by RT-PCR and immunohistochemistry, respectively, in Peking duck at different stages of development. Ghrelin mRNA expression was mainly detected in the proventriculus and proventricu...
Source: General and Comparative Endocrinology - November 12, 2009 Category: Endocrinology Authors: Shao Y, Liu S, Tang X, Gao J, Wu G, Li Z Tags: Gen Comp Endocrinol Source Type: journals

Cholecystokinin: Molecular Cloning and Immunohistochemical Localization in the Gastrointestinal Tract of Larval Red Drum, Sciaenops ocellatus (L.).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The current study sought to clarify the role of cholecystokinin (CCK) in the digestion of larval red drum (Sciaenops ocellatus) in order to better characterize the processes limiting the utilization of microparticulate diets at first feeding. The red drum CCK cDNA, isolated from adult anterior intestine and pyloric caeca, contains a 414 base pair (bp) open reading frame encoding a deduced amino acid sequence of 138 residues which is highly similar to preprocholecystokinin from other vertebrates. The mature CCK octapeptide has the same amino acid sequence as that found in mammals and in Atlantic herring (Clupea harengus...
Source: General and Comparative Endocrinology - November 5, 2009 Category: Endocrinology Authors: Webb Jr KA, Khan IA, Nunez BS, Rønnestad I, Holt GJ Tags: Gen Comp Endocrinol Source Type: journals

Ghrelin decreases food intake in juvenile rainbow trout (Oncorhynchus mykiss) through the central anorexigenic corticotropin-releasing factor system.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ghrelin stimulates pituitary growth hormone (GH) release, and has a key role in the regulation of food intake and adiposity in vertebrates. To investigate the central effect of native rainbow trout ghrelin (rtghrelin) on food intake in rainbow trout, as well as its possible mode of action, four groups of fish received a single injection into the third brain ventricle (i.c.v. injection): (1) control group (physiological saline) (2) ghrelin-treated group (2.0 ng rtghrelin g bwt(-1)), (3) group given the corticotropin-releasing hormone receptor antagonist alpha-Helical CRF 9-41 (ahCRF) (4.0 ng g bwt(-1)) and (4) group rec...
Source: General and Comparative Endocrinology - November 5, 2009 Category: Endocrinology Authors: Jönsson E, Kaiya H, Björnsson BT Tags: Gen Comp Endocrinol Source Type: journals

In Vivo but not In Vitro Leptin Enhances Lymphocyte Proliferation in Siberian Hamsters (Phodopus sungorus).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mounting an immune response requires a relatively substantial investment of energy and marked reductions in energy availability can suppress immune function and presumably increase disease susceptibility. We have previously demonstrated that a moderate reduction in energy stores by partial surgical lipectomy impairs humoral immunity of Siberian hamsters (Phodopus sungorus) and is mediated, in part, by changes in the adipose tissue hormone leptin. The goals of the present study were to assess the role of leptin in cell-mediated immunity and to determine if the potential effects of leptin on immunity are via the direct a...
Source: General and Comparative Endocrinology - November 5, 2009 Category: Endocrinology Authors: Demas GE Tags: Gen Comp Endocrinol Source Type: journals

Gene structure, recombinant expression and functional characterization of grass carp leptin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Leptin is an important hormone for the regulation of food intake, energy expenditure and reproduction in mammals, but information regarding its role in teleosts remains scant. In the present study, the gene structures of grass carp (Ctenopharyngodon idellus) and silver carp (Hypophthalmichthys molitrix) leptins were characterized. Recombinant grass carp leptin (rgc-LEP) was expressed in E. coli and purified, and identified by mass spectrometric analysis. A strong anorexic effect on food intake was observed in grass carp on the first day after intraperitoneal (IP) injection of rgc-LEP, but not during the following days....
Source: General and Comparative Endocrinology - October 23, 2009 Category: Endocrinology Authors: Li GG, Liang XF, Xie Q, Li G, Yu Y, Lai K Tags: Gen Comp Endocrinol Source Type: journals

Maternal Androgen Levels During Pregnancy are Associated with Early-life Growth in Geoffroy's Marmosets, Callithrix geoffroyi.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Fetal development is a critical period of physical development, and factors in the intrauterine environment can cause lasting effects on the growth and development of offspring. There is little research evaluating organizational effects of early androgen exposure of endogenous maternal origins on the prenatal and postnatal growth of offspring. We evaluated the association between maternal androgen levels during gestation and pre- and postnatal growth of offspring. Maternal androgen levels in marmoset females were measured using enzyme immunoassays of urine samples acquired during 18 pregnancies. Somatic measurements of...
Source: General and Comparative Endocrinology - October 22, 2009 Category: Endocrinology Authors: Smith AS, Birnie AK, French JA Tags: Gen Comp Endocrinol Source Type: journals

A Novel Prolactin-like Protein (PRL-L) Gene in Chickens and Zebrafish: Cloning and Characterization of Its Tissue Expression.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a full-length cDNA encoding a prolactin-like protein (PRL-L) was cloned from chicken brain tissues using RT-PCR. This putative PRL-L precursor has 225 amino acids in length and shares 30-35% amino acid sequence identity with prolactin (PRL) of chicken, zebrafish, Xenopus, rat and human. Using RT-PCR, the mRNA expression of PRL-L in chicken tissues was further examined. Unlike the predominant expression of PRL in pituitary, PRL-L was found to be widely expressed in adult chicken extra-pituitary tissues with only minimal expression detected in pituitary. In day-7 chicken embryos, the expression of PRL-L, but n...
Source: General and Comparative Endocrinology - October 22, 2009 Category: Endocrinology Authors: Wanga Y, Li J, Yan Kwok AH, Ge W, Leung FC Tags: Gen Comp Endocrinol Source Type: journals

Fish with thermolabile sex determination (tsd) as models to study brain sex differentiation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
As fish are ectothermic animals, water temperature can affect their basic biological processes such as larval development, growth and reproduction. Similar to reptiles, the incubation temperature during early phases of development is capable to modify sex ratios in a large number of fish species. This phenomenon, known as thermolabile sex determination (TSD) was first reported in Menidia menidia, a species belonging to the family Atherinopsidae. Since then, an increasing number of fish have also been found to exhibit TSD. Traditionally, likewise in reptiles, several TSD patterns have been described in fish, however it ...
Source: General and Comparative Endocrinology - October 22, 2009 Category: Endocrinology Authors: Blázquez M, Somoza GM Tags: Gen Comp Endocrinol Source Type: journals

Production, characterization, and applications of mouse monoclonal antibodies against gonadotropin, somatolactin, and prolactin from common carp (Cyprinus carpio).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The gonadotropin alpha subunit (cGTHalpha), gonadotropinIIbeta subunit (cGTHIIbeta), somatolactin (cSL), and prolactin (cPRL) were isolated from the pituitaries of common carps, purified by traditional chromatographic analysis, identified by mass-chromatographic analysis, and used as immunogens in the B-lymphocyte hybridoma technique. Totally, 7, 11, 17, and 8 hybridoma cell lines were established, which were able to stably secrete monoclonal antibodies (mAbs) against cGTHalpha, cGTHIIbeta, cSL, and cPRL, and designated as FMU-cGTHalpha1-7, FMU-cGTHIIbeta1-11, FMU-cSL 1-17, and FMU-cPRL 1-8, respectively. The isotype, ...
Source: General and Comparative Endocrinology - October 22, 2009 Category: Endocrinology Authors: Xu Z, Li Q, Wang Y, Song C, Zhang T, Chen L, Ji J, Yang A, Zhu Z, Hu W, Jin B Tags: Gen Comp Endocrinol Source Type: journals

Is there a leptin gene in the chicken genome? Lessons from phylogenetics, bioinformatics and genomics.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19854194 [PubMed - as supplied by publisher] (Source: General and Comparative Endocrinology)
Source: General and Comparative Endocrinology - October 22, 2009 Category: Endocrinology Authors: Pitel F, Faraut T, Bruneau G, Monget P Tags: Gen Comp Endocrinol Source Type: journals

Annual cycles of urinary reproductive steroid concentrations in wild and captive endangered Fijian ground frogs (Platymantis vitiana).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Annual cycles of reproductive steroid metabolites were measured in urine collected from free-living and captive tropical Fijian ground frogs (Platymantis vitiana) in the first study of urinary reproductive steroids in an endangered amphibian species. Free-living frogs were sampled on Viwa Island, Fiji and captive frogs were maintained in an outdoor enclosure in Suva, Fiji. Urinary estrone, progesterone and testosterone metabolite concentrations increased in male and female frogs after hCG challenges, with clear peaks in steroid concentrations two or three days after the challenges. There were annual cycles of testoster...
Source: General and Comparative Endocrinology - October 15, 2009 Category: Endocrinology Authors: Narayan EJ, Molinia FC, Christi KS, Morley CG, Cockrem JF Tags: Gen Comp Endocrinol Source Type: journals

PKC mediates GnRH activation of a Na(+)/H(+) exchanger in goldfish somatotropes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Previous results suggest that gonadotropin-releasing hormone (GnRH) stimulation of somatotropin secretion in goldfish involves activation of Na(+)/H(+) exchange (NHE). We tested the hypothesis that GnRH alkalinizes intracellular pH (pH(i)) via protein kinase C (PKC) activation of NHE. Two types of alkalinization responses were observed in identified goldfish somatotropes preloaded with the pH-sensitive dye BCECF; the rate of pH(i) changes went from a neutral or slightly negative slope to either a positive or a less negative slope relative to control. Two GnRHs, the PKC-activating TPA, and dioctanoyl glycerol each cause...
Source: General and Comparative Endocrinology - October 12, 2009 Category: Endocrinology Authors: Li GL, Parks SK, Goss GG, Chang JP Tags: Gen Comp Endocrinol Source Type: journals

Association between pituitary adenylate cyclase activating polypeptide and reproduction in the blue gourami.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In order to gain a better understanding of the roles of pituitary adenylate cyclase-activating polypeptide (PACAP) in reproduction and growth, the expression of the PACAP gene during the reproduction cycle and its potential role in regulating gonadotropin and growth hormone (GH) gene transcription in blue gourami were investigated. The cDNA sequences of the full-length blue gourami brain PACAP and that of its related peptide (PRP) were acquired. PACAP cDNA had two variants, obtainable by alternative splicing: a long form encoding for both PRP and PACAP and a short form encoding only for PACAP. In females, mRNA levels o...
Source: General and Comparative Endocrinology - October 9, 2009 Category: Endocrinology Authors: Levy G, Goldberg D, Jackson K, Degani G Tags: Gen Comp Endocrinol Source Type: journals

Effect of melatonin in the antioxidant defense system in the locomotor muscles of the estuarine crab Neohelice granulata (Decapoda,Brachyura).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, melatonin in the locomotor muscles of N.granulata affects the antioxidant/pro-oxidant balance in a time and dosage dependent manner. PMID: 19818787 [PubMed - as supplied by publisher] (Source: General and Comparative Endocrinology)
Source: General and Comparative Endocrinology - October 6, 2009 Category: Endocrinology Authors: Geihs MA, Vargas MA, Maciel FE, Caldas SS, Cruz BP, Primel EG, Monserrat JM, Nery LE Tags: Gen Comp Endocrinol Source Type: journals

Endocrine Interactions Between Plants and Animals: Implications of exogenous hormone sources for the evolution of hormone signaling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hormones are central to animal physiology, metabolism and development. Details on signal transduction systems and regulation of hormone synthesis, activation and release have only been studied for a small number of animal groups, notably arthropods and chordates. However, a significant body of literature suggests that hormonal signaling systems are not restricted to these phyla. For example, work on several echinoderm species shows that exogenous thyroid hormones (THs) affect larval development and metamorphosis and our new data provide strong evidence for endogenous synthesis of THs in sea urchin larvae. In addition t...
Source: General and Comparative Endocrinology - October 6, 2009 Category: Endocrinology Authors: Miller AE, Heyland A Tags: Gen Comp Endocrinol Source Type: journals

Gonadotropin-Releasing Hormone-Like Molecule Is Not an Acute Reproductive Activator in the Gastropod, Aplysia californica.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we characterized the distribution and quantity of ap-GnRH peptide in several central and peripheral tissues of A. californica. Further, we performed in vivo and in vitro studies to explore the function of ap-GnRH in these animals. Immunohistochemistry and radioimmunoassay using specific antisera against ap-GnRH showed that pedal ganglia contained the highest level of ap-GnRH peptide, followed by cerebral ganglia, abdominal ganglia, and then buccal ganglia. Ovotestis did not contain detectable levels of ap-GnRH peptide. Injection of sexually mature and immature animals with synthetic ap-GnRH over a course of ...
Source: General and Comparative Endocrinology - September 30, 2009 Category: Endocrinology Authors: Tsai PS, Sun B, Rochester JR, Wayne NL Tags: Gen Comp Endocrinol Source Type: journals

Combined antisense knockdown of type 1 and type 2 iodothyronine deiodinases disrupts embryonic development in zebrafish (Danio rerio).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Thyroid hormones (THs) are important regulators of gene expression during vertebrate development. In teleosts, early embryos rely on the maternal TH deposit in the egg yolk, consisting predominantly of T(4). Activation of T(4) to T(3) by iodothyronine deiodinases (Ds) may therefore be an important factor in determining T(3)-dependent development. In zebrafish, both Ds capable of T(3) production, D1 and D2, are first expressed very early during embryonic development. We sought to determine their relative importance for zebrafish embryonic development by inhibiting their expression via antisense oligonuleotides against D...
Source: General and Comparative Endocrinology - September 29, 2009 Category: Endocrinology Authors: Walpita CN, Crawford AD, Darras VM Tags: Gen Comp Endocrinol Source Type: journals

Anandamide and AM251, via water, modulate food intake at central and peripheral level in fish.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The endocannabinoid system is a major regulator of food intake in many animal species. Studies conducted so far have mostly focused on mammals, and, therefore, in this study, the role of the endocannabinoid system in food intake in the sea bream Sparus aurata was investigated. The effect of different doses of the endocannabinoid anandamide (AEA), administered via water, was evaluated after different exposure times (30, 60 and 120 minutes) at both physiological and molecular levels. The results obtained indicate that fish exposed to AEA via water present approximately 1000-fold higher levels of AEA in both the brain and...
Source: General and Comparative Endocrinology - September 29, 2009 Category: Endocrinology Authors: Piccinetti CC, Migliarini B, Petrosino S, Marzo VD, Carnevali O Tags: Gen Comp Endocrinol Source Type: journals

Expression and localization of the deubiquitinating enzyme mUBPy in wobbler mouse testis during spermiogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, in wobbler testis expression of mUbpy is up-regulated, while a differential sorting of the protein characterizes wobbler spermatids where acrosome formation is impaired. PMID: 19800341 [PubMed - as supplied by publisher] (Source: General and Comparative Endocrinology)
Source: General and Comparative Endocrinology - September 29, 2009 Category: Endocrinology Authors: Chianese R, Scarpa D, Berruti G, Cobellis G, Pierantoni R, Fasano S, Meccariello R Tags: Gen Comp Endocrinol Source Type: journals

Regulation of pituitary GnRH receptor and gonadotropin subunits by IGF1 and GnRH in prepubertal male coho salmon.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study examined effects of IGF1 alone or in combination with gonadotropin-releasing hormone (GnRH) on pituitary transcripts for GnRH receptor (GnRHR) variants, follicle-stimulating hormone (FSH), luteinizing hormone (LH), growth hormone (GH) and IGF, as well as secretion of FSH in vitro. Three experiments were conducted with dispersed pituitary cells of prepubertal male coho salmon (Oncorhynchus kisutch) to determine the time course of the response to IGF1, IGF1 concentration response, and GnRH concentration response. IGF1 consistently elevated pituitary transcripts for gnrhr1 and the four gonadotropin subunits (fshb, ...
Source: General and Comparative Endocrinology - September 29, 2009 Category: Endocrinology Authors: Luckenbach JA, Dickey JT, Swanson P Tags: Gen Comp Endocrinol Source Type: journals

Endocrine disruption and ovarian morphometric responses in rats following exposure to tetradifon.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have investigated whether exposure to tetradifon causes ovary injuries, disrupts folliculogenesis in rat and whether ovary hormones (estrogen and progesterone) to be affected by this endocrine-active agent. Female rats were exposed orally to a dose of 28.9 mg/kg/day for 6 or 12 weeks. After sacrifice, ovary glands were examined for morphometric changes. The serums were used to determine levels of 17beta-estradiol and progesterone. Results showed no sign of toxicity. However, tetradifon promoted a significant increase in the percentage of atretic follicles in the 12-weeks treated rats. Number and the diameter of matu...
Source: General and Comparative Endocrinology - September 29, 2009 Category: Endocrinology Authors: Badraoui R, Abdelmoula NB, Feki N, Nasr HB, Rebai T Tags: Gen Comp Endocrinol Source Type: journals

Molecular Characterization, Appetite Regulatory Effects and Feeding Related Changes of Peptide YY in Goldfish.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we identified the gene organization of goldfish PYY (gfPYY) and found abundant expression of PYY mRNA in the brain and digestive tract of goldfish. A 2.5 fold increase at 3 hours post-feeding and a 1.5 fold decrease in fasted animals was observed of PYY mRNA expression in the brain, suggesting an anorectic role for PYY in goldfish. A single intraperitoneal injection of 10 ng/g body weight gfPYY(1-36) or an intracerebroventricular injection of 5 ng/g body weight gfPYY(1-36) caused a 27% or 33% reduction in food intake in goldfish, respectively. Overall, our results, for the first time provide molecular and fu...
Source: General and Comparative Endocrinology - September 29, 2009 Category: Endocrinology Authors: Gonzalez R, Unniappan S Tags: Gen Comp Endocrinol Source Type: journals

Spatial Localization of EGF Family Ligands and Receptors in the Zebrafish Ovarian Follicle and Their Expression Profiles during Folliculogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The roles of epidermal growth factor (EGF) family in the ovary have received increasing attention recently. Despite this, the production sites of EGF family members in the ovarian follicle still remain controversial. Using zebrafish as the model, the present study investigated spatial distribution of several EGF family ligands and receptors in the follicle as well as their temporal expression profiles during folliculogenesis. RT-PCR analysis on the somatic follicle layer and oocyte revealed that all EGF family ligands examined (egf, tgfa, btc and hbegf) were mostly or exclusively expressed in the oocyte. In contrast, t...
Source: General and Comparative Endocrinology - September 28, 2009 Category: Endocrinology Authors: Tse AC, Ge W Tags: Gen Comp Endocrinol Source Type: journals

Variation in plasma leptin-like immunoreactivity in free-living European starlings (Sturnus vulgaris).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Leptin, a protein hormone secreted by fat cells, is best known for its role as an adiposity signal; however, leptin has diverse physiological roles ranging from regulation of feeding behavior and body weight, to effects on reproduction and immune function. Although leptin has been extensively studied in mammals, the identification and function of leptin in birds remains controversial, and studies have focused on captive or domesticated species. Here, we describe changes in plasma leptin-like immunoreactivity during the reproductive and non-reproductive seasons in free-living female European starlings (Sturnus vulgaris)...
Source: General and Comparative Endocrinology - September 27, 2009 Category: Endocrinology Authors: Kordonowy LL, McMurtry JP, Williams TD Tags: Gen Comp Endocrinol Source Type: journals

Temporal mRNA expression of transforming growth factor-beta superfamily members and inhibitors in the developing rainbow trout ovary.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
During mammalian ovarian development transforming growth factor-beta (TGFbeta) superfamily members and their inhibitors are critical paracrine regulators, yet the intraovarian functions of these proteins have received less attention in fish. Using quantitative real-time RT-PCR, changes in ovarian mRNA expression of six TGFbeta members and two inhibitors were investigated in rainbow trout across a wide range of fish ovarian stages (i.e., early perinucleous stage through acquisition of maturational competence). Transcript changes for insulin-like growth factor 1 and 2, and five enzymes associated with steroidogenesis, as...
Source: General and Comparative Endocrinology - September 21, 2009 Category: Endocrinology Authors: Lankford SE, Weber GM Tags: Gen Comp Endocrinol Source Type: journals

Temporal expression of hepatic estrogen receptor 1, vitellogenin1 and vitellogenin2 in European silver eels.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we followed the hepatic vitellogenesis upon four weekly injections with carp pituitary extracts (CPE). New molecular primers for the expression of the estrogen receptor 1 (esr1), vitellogenin1 (vtg1) and vitellogenin2 (vtg2) in the liver were developed. Sequences of vtg2 and esr1 were not previously described in Anguilla anguilla. All eels showed weekly increase of the eye size and pectoral fin length, which are signs of early maturation. The same occurred with the gonadosomatic index, the oocyte stage and diameter, and number of deposited fat droplets. Early vitellogenesis appeared as a 3-step process: 1) E2...
Source: General and Comparative Endocrinology - September 16, 2009 Category: Endocrinology Authors: Palstra AP, Schnabel D, Nieveen MC, Spaink HP, van den Thillart GE Tags: Gen Comp Endocrinol Source Type: journals

Activation of the Black Seabream (Acanthopagrus schlegeli) Somatolactin- alpha Gene Promoter by Pit-1c in the Hepa T1 Cell-line.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Somatolactin (SL) is a pituitary hormone of the growth hormone (GH) gene family found only in fish. To understand the regulation of this hormone at the level of gene transcription, we obtained a SLalpha gene from black seabream (bsb), with its 5' flanking promoter region carrying several putative transcription factors including seven binding sites for pituitary specific transcription factor 1 (Pit-1). To study the actions of Pit-1 on this gene promoter, we cloned three variants of bsbPit-1 (Pit-1a, Pit-1b and Pit-1c) derived from alternative splicing of mRNA or differential transcription start sites from black seabream...
Source: General and Comparative Endocrinology - September 15, 2009 Category: Endocrinology Authors: Tian J, Chan KM Tags: Gen Comp Endocrinol Source Type: journals

In search for a common denominator for the diverse functions of Arthropod Corazonin: a role in the physiology of stress?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Corazonin (Crz) is an 11 amino acid C-terminally amidated neuropeptide that has been identified in most arthropods examined with the notable exception of beetles and an aphid. The Crz receptor shares sequence similarity to the GnRH-AKH receptor family thus suggesting an ancestral function related to the control of reproduction and metabolism. In 1989, Crz was purified and identified as a potent cardioaccelerating agent in cockroaches (hence the Crz name based on "corazon", the Spanish word for "heart"). Since the initial assignment as a cardio-acceleratory peptide, additional functions have been discovered, ranging fro...
Source: General and Comparative Endocrinology - September 9, 2009 Category: Endocrinology Authors: Boerjan B, Verleyen P, Huybrechts J, Schoofs L, Loof AD Tags: Gen Comp Endocrinol Source Type: journals

Influence of intrinsic signals and environmental cues on the endocrine control of feeding in fish: potential application in aquaculture.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Optimization of food consumption and ultimately growth are major concerns for aquaculture. In fish, food intake is regulated by several hormones produced by both brain and peripheral tissues. Changes in feeding behavior and appetite usually occur through the modulation of the gene expression and/or action of these appetite-regulating hormones and can be due not only to variations in intrinsic factors such as nutritional/metabolic or reproductive status, but also to changes in environmental factors, such as temperature and photoperiod. In addition, the gene expression and /or plasma levels of appetite-regulating hormone...
Source: General and Comparative Endocrinology - September 3, 2009 Category: Endocrinology Authors: Volkoff H, Hoskins LJ, Tuziak SM Tags: Gen Comp Endocrinol Source Type: journals

Somatostatin and Somatostatin Receptors in Fish Growth.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Multiple forms of somatostatin (SS) and SS receptors (SSTR) are produced widely in the tissues of fish and interact to coordinate numerous physiological processes. Insight into their role in growth regulation emerged from studies of abnormal growth and of whole animals. The influence of SS on organismal growth operates at several levels of the growth hormone (GH)-insulin-like growth factor-1 (IGF-1) system. SS inhibits production and release of pituitary GH, but not all forms of SS are equipotent in this action. SS also influences the GH-IGF-1 system in an extrapituitary manner by reducing sensitivity to GH as well as ...
Source: General and Comparative Endocrinology - September 3, 2009 Category: Endocrinology Authors: Sheridan MA, Hagemeister AL Tags: Gen Comp Endocrinol Source Type: journals

9th International Symposium on Avian Endocrinology.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19596222 [PubMed - in process] (Source: General and Comparative Endocrinology)
Source: General and Comparative Endocrinology - July 16, 2009 Category: Endocrinology Authors: Sharp PJ, Decuypere E, Darras V Tags: Gen Comp Endocrinol Source Type: journals

Changes in the plasma levels of insulin-like growth factor-I from the onset of spawning migration through upstream migration in chum salmon.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, the plasma IGF-I levels increased with gonadal development when chum salmon migrated from the winter Gulf of Alaska to the summer Bering Sea. Circulating IGF-I may interact with the PG-axis and promote gonadal development that is inseparable from the onset of spawning migration. Circulating IGF-I levels were thereafter lowered in accordance with final maturation during upstream migration in the breeding season. PMID: 19595688 [PubMed - as supplied by publisher] (Source: General and Comparative Endocrinology)
Source: General and Comparative Endocrinology - July 8, 2009 Category: Endocrinology Authors: Onuma TA, Makino K, Katsumata H, Beckman BR, Ban M, Ando H, Fukuwaka MA, Azumaya T, Swanson P, Urano A Tags: Gen Comp Endocrinol Source Type: journals

Cxcl12a-Cxcr4b signaling is important for proper development of the forebrain GnRH system in zebrafish.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hypothalamic gonadotropin-releasing hormone (GnRH) neurons control pituitary gonadotropin secretion and gametogenesis. In the course of development, these neurons migrate from the olfactory placode to the hypothalamus. The precise molecular mechanism of this neuronal migration is unclear. Here, we investigated whether the chemokine receptor, Cxcr4b, and its cognate ligand, Cxcl12a, are required for proper migration of GnRH3 neurons in zebrafish. Deviated GnRH3 axonal projections and neuronal migration were detected in larvae that carry a homozygote cxcr4b mutation. Similarly, knockdown of Cxcr4b or Cxcl12a led to the a...
Source: General and Comparative Endocrinology - July 8, 2009 Category: Endocrinology Authors: Palevitch O, Abraham E, Borodovsky N, Levkowitz G, Zohar Y, Gothilf Y Tags: Gen Comp Endocrinol Source Type: journals

Suppressed Production of Methyl Farnesoid Hormones Yields Developmental Defects and Lethality in Drosophila Larvae.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A long-unresolved question in the developmental biology of Drosophila melanogaster has been whether methyl farnesoid hormones secreted by the ring gland are necessary for larval maturation and metamorphosis. In the present study, we have used RNAi techniques to inhibit 3-Hydroxy-3-Methylglutaryl CoA Reductase (HMGCR) expression selectively in the corpora allatal cells that produce the circulating farnesoid hormones. The developing larvae manifest a number of developmental, metabolic and morphogenetic derangements. These defects included the exhibition of an "ultraspiracle" death phenotype at the 1(st) to 2(nd) larval m...
Source: General and Comparative Endocrinology - July 8, 2009 Category: Endocrinology Authors: Jones D, Jones G, Teal P, Hammac C, Messmer L, Osborne K, Belgacem YH, Martin JR Tags: Gen Comp Endocrinol Source Type: journals

Development of the Adrenal Stress Response in the Florida scrub-jay (Aphelocoma coerulescens).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined this hypothesis in Florida scrub-jays, a cooperatively-breeding species with altricial young. Blood samples were collected from nestlings, nutritionally independent young, and yearlings for measurement of corticosterone levels. Baseline corticosterone levels did not differ between age classes; however, stress-induced corticosterone levels were highest in yearlings, intermediate in independent young, and lowest in nestlings. The nestling stress response was also of a shorter duration than the response in independent young and yearlings. This variation in stress responsiveness across ages may be an adaptive mecha...
Source: General and Comparative Endocrinology - July 8, 2009 Category: Endocrinology Authors: Rensel MA, Boughton RK, Schoech SJ Tags: Gen Comp Endocrinol Source Type: journals

The onset of cortisol synthesis and the stress response is independent of changes in CYP11B or CYP21 mRNA levels in larval red drum (Sciaenops ocellatus).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although cortisol plays an important role in teleost development, the onset of cortisol production and the cortisol stress response in teleosts remain poorly understood. Here we have reported basal cortisol levels and the development of the cortisol stress response in larval red drum (Sciaenops ocellatus). We isolated partial nucleic acid sequences encoding two key corticosteroidogenic enzymes, CYP11B and CYP21 and assessed ontogenetic patterns of their mRNA levels relative to basal and stress-induced cortisol production. Basal cortisol was first detected 3 days post-hatch (DPH) and reached a maximum at 9 DPH. Cortisol...
Source: General and Comparative Endocrinology - July 8, 2009 Category: Endocrinology Authors: Applebaum SL, Wilson CA, Holt GJ, Nunez BS Tags: Gen Comp Endocrinol Source Type: journals

Stress and Fish Reproduction: The Roles of Allostasis and Hormesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper is a review of the effects of stress on reproduction in fishes. I hope to further the development of the concepts of allostasis and hormesis as relevant to understanding reproduction in general and in fish in particular. The main contentions I derive in this review are the following: Stressors affect fish reproduction in a variety of ways depending on the nature and severity of the stressor. The effects are transduced through a hormonal cascade initiated by perception of the stressor and involving the hypothalamus-pituitary-interrenal axis, the catecholamines, and also cytokines. Mounting a stress response a...
Source: General and Comparative Endocrinology - July 7, 2009 Category: Endocrinology Authors: Schreck CB Tags: Gen Comp Endocrinol Source Type: journals

Expression analysis of steroid hormone receptor mRNAs during zebrafish embryogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have analyzed by qRT-PCR and/or RT/PCR the abundance and degradation rate of maternal mRNAs for nine steroid hormone receptors and their possible replacement by corresponding embryonic transcripts in both ovulated oocytes and embryos of zebrafish collected at 0, 1, 2, 4, 8, 12, 24 and 48 h post-fertilization (hpf). The mRNAs encoded the nuclear receptors for progesterone (Pr), androgen (Ar), estrogen (Eralpha, Er beta1 and Er beta2), glucocorticoids (Gr), mineralocorticoids (Mr) and the membrane progestin receptor-alpha and beta (mPralpha and beta). Gr mRNA was the most abundant maternal transcript in oocytes and ea...
Source: General and Comparative Endocrinology - June 30, 2009 Category: Endocrinology Authors: Pikulkaew S, De Nadai A, Belvedere P, Colombo L, Valle LD Tags: Gen Comp Endocrinol Source Type: journals

Female androgen patterns and within-pair testosterone compatibility in domestic geese (Anser domesticus).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
For successfully raising offspring, long-term monogamous pair partners need to be behaviorally and hormonally coordinated. In the monogamous, biparental greylag geese (Anser anser) a dyadic pairbond-specific measure, 'within-pair testosterone compatibility' (TC) indicated how closely synchronized are seasonal androgen levels, which co-varied with reproductive output. Males, in particular, were assumed to respond to their females' hormonal and fecundity phases. We now present experiments with biparental domestic geese (A. domesticus) kept as pairs to ask whether TC occurs also in these generally polygynous animals. We f...
Source: General and Comparative Endocrinology - June 29, 2009 Category: Endocrinology Authors: Hirschenhauser K, Weiß BM, Haberl W, Möstl E, Kotrschal K Tags: Gen Comp Endocrinol Source Type: journals

Fecal Endocrine Profiles and Ejaculate Traits in Black-Footed Cats (Felis nigripes) and Sand Cats (Felis margarita).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Information regarding the reproductive biology of black-footed cats (BFC) and sand cats (SC) is extremely limited. Our objectives were to: 1) validate fecal hormone analysis (estrogens, E; progestagens, P; androgens, T) for noninvasive monitoring of gonadal activity; 2) characterize estrous cyclicity, ovulatory mechanisms, gestation, and seasonality; and 3) evaluate male reproductive activity via fecal androgen metabolites and ejaculate traits. In both species, the estrous cycle averaged 11-12 days. In BFC (n=8), estrus lasted 2.2 +/- 0.2 days with peak concentrations of E (2962.8 +/- 166.3 ng/g feces) increasing 2.7 f...
Source: General and Comparative Endocrinology - June 29, 2009 Category: Endocrinology Authors: Herrick JR, Bond JB, Campbell M, Levens G, Moore T, Benson K, D'Agostino J, West G, Okeson DM, Coke R, Portacio SC, Leiske K, Kreider C, Polombo PJ, Swanson WF Tags: Gen Comp Endocrinol Source Type: journals

treatment with arginine vasotocin alters mating calls and decreases call attractiveness in male túngara frogs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we investigate the effects of AVT on call characteristics in the túngara frog (Physalaemus pustulosus). Túngara frogs produce a "whine" that is important for species recognition; they may also produce a second, attractive call component, the "chuck". We used a field playback experiment to determine changes in male calling behavior following treatment with AVT. A previous study showed that AVT alters call rate and the production of chucks; in the current analysis, we focus on changes in the whine. Males produce shorter whines with higher initial frequencies following treatment with AVT. Call changes...
Source: General and Comparative Endocrinology - June 29, 2009 Category: Endocrinology Authors: Kime NM, Whitney TK, Ryan MJ, Rand AS, Marler CA Tags: Gen Comp Endocrinol Source Type: journals

"Gen Comp Endocrinol"[ta]; +114 new citationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
114 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: "Gen Comp Endocrinol"[ta] These pubmed results were generated on 2009/06/27PubMed, a service of the National Library of Medicine, includes over 15 million citations for biomedical articles back to the 1950's. These citations are from MEDLINE and additional life science journals. PubMed includes links to many sites providing full text articles and other related resources. (Source: General and Comparative Endocrinology)
Source: General and Comparative Endocrinology - June 27, 2009 Category: Endocrinology Tags: Report Source Type: journals

Seasonal changes in gonadal expression of gonadotropin receptors, steroidogenic acute regulatory protein and steroidogenic enzymes in the European sea bass.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aimed to investigate transcript levels of both gonadotropin receptors (FSHR and LHR) during an entire reproductive cycle in male and female sea bass (Dicentrarchus labrax). To have a more comprehensive understanding of how different key factors interact to control sea bass gonadal function, changes in the transcript abundance of two important steroidogenic enzymes, P450 11beta-hydroxylase (CYP11B1) and P450 aromatase (CYP19A1), and the steroidogenic acute regulatory protein (StAR), were also studied. These expression profiles were analysed in relation to changes in the plasma levels of important reproductive hor...
Source: General and Comparative Endocrinology - April 2, 2009 Category: Endocrinology Authors: Rocha A, Zanuy S, Carrillo M, Gómez A Tags: Gen Comp Endocrinol Source Type: journals

Ultrasonography of Reproductive Structures and Hormonal Correlates of Follicular Development in Female American Alligators, Alligator mississippiensis, in Southwest Louisiana.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present results from a study testing the efficacy of using ultrasonography to monitor reproduction in the American alligator, Alligator mississippiensis. Ultrasound results were then compared with plasma hormone levels. A total of 124 females were examined during March, April, May, and early June (2001-2003). Ultrasound results were validated on a series of reproductive females (n=14) necropsied for other studies. Previtellogenic follicles, vitellogenic follicles, recently shelled eggs, fully developed well-calcified eggs, and atretic follicles were readily discernible with ultrasound in mature females. Reproductive str...
Source: General and Comparative Endocrinology - March 31, 2009 Category: Endocrinology Authors: Lance VA, Rostal DC, Elsey RM, Trosclair Iii PL Tags: Gen Comp Endocrinol Source Type: journals

Central hyperventilatory action of the stress-related neurohormonal peptides, corticotropin-releasing factor and urotensin-I in the trout Oncorhynchus mykiss.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The stress-related neurohormonal peptides corticotropin-releasing factor (CRF) and urotensin-I (U-I), an ortholog of mammalian urocortin 1, are widely distributed in the central nervous systems of teleost fish but little is known about their possible central neurotropic actions. In the present study, we investigated the effect of intracerebroventricular (ICV) injection of CRF and U-I (1-10 pmol) on ventilatory and cardiovascular variables in our established unanaesthetized trout model. CRF and U-I produced a significant dose-dependent and long-lasting increase in the ventilatory frequency (VF) and the ventilatory ampli...
Source: General and Comparative Endocrinology - March 30, 2009 Category: Endocrinology Authors: Mével JC, Lancien F, Mimassi N, Conlon JM Tags: Gen Comp Endocrinol Source Type: journals