In vitro effects of gonadotropin-releasing hormone (GnRH) on Leydig cells of adult alpaca (Lama pacos) testis: GnRH receptor immunolocalization, testosterone and prostaglandin synthesis, and cyclooxygenase activities     

Zerani M  Catone G  Quassinti L  Maccari E  Bramucci M  Gobbetti A  Maranesi M  Boiti C  Parillo F 《Domestic animal endocrinology》2011,40(1):51-59

The main objective of this study was to examine the modulatory in vitro effects of gonadotropin-releasing hormone (GnRH) on isolated Leydig cells of adult alpaca (Lama pacos) testis. We first evaluated the presence of GnRH receptor (GnRHR) and cyclooxygenase (COX) 1 and COX2 in alpaca testis. We then studied the in vitro effects of buserelin (GnRH analogue), antide (GnRH antagonist), and buserelin plus antide or inhibitor of phospholipase C (compound 48/80) and COXs (acetylsalicylic acid) on the production of testosterone, PGE(2), and PGF(2α) and on the enzymatic activities of COX1 and COX2. Immunoreactivity for GnRHR was detected in the cytoplasm of Leydig cells and in the acrosomal region of spermatids. COX1 and COX2 immunosignals were noted in the cytoplasm of spermatogonia, spermatocytes, spermatids, Leydig cells, and Sertoli cells. Western blot analysis confirmed the GnRHR and COX1 presence in alpaca testis. The in vitro experiments showed that buserelin alone increased (P < 0.01) and antide and buserelin plus acetylsalicylic acid decreased (P < 0.01) testosterone and PGF(2α) production and COX1 activity, whereas antide and compound 48/80 counteracted buserelin effects. Prostaglandin E(2) production and COX2 activity were not affected by buserelin or antide. These data suggest that GnRH directly up-regulates testosterone production in Leydig cells of adult alpaca testis with a postreceptorial mechanism that involves PLC, COX1, and PGF(2α).  相似文献   

GnRH和LHR基因多态性和牛精液品质性状的相关分析     

孙丽萍  杜青之  宋亚攀  杨武才  于俊娜  熊家军  杨利国 《中国奶牛》2011,(22):5-8

本试验采用PCR—RFLP方法分析了GnRH基因外显子2和LHR基因内含子9在144头中国荷斯坦牛和79头河南地方肉牛品种中的多态性,利用最小二乘法分析多态位点不同基因型与精液品质性状的关系。研究结果表明,2～3岁荷斯坦牛的鲜精活力显著高于4岁以上的牛,而畸形率显著低于7岁以上的牛。对2～4岁荷斯坦牛不同精液品质性状的简单相关分析表明,畸形率与顶体完整率和冻精活力呈显著的负相关（相关系数r分别为-0．736和-0．500）。不同基因型与精液品质性状的关联分析结果表明,144头中国荷斯坦牛所研究位点不同基因型对精液品质性状没有显著影响。而河南地方肉牛GnRH基因外显子2的A883G位点GG基因型的精子密度显著低于AA和AG基因型．LHR基因G51656T位点的TT基因型精子密度显著高于GT基因型,未检测到GG基因型。并且发现随着年龄的增长,种公牛的精液品质逐渐变差。GnRH和LHR基因可作为影u向肉牛精液品质性状的候选基因。  相似文献   

Effect of luteinizing hormone oscillations on progesterone concentrations based on treatment with a gonadotropin-releasing hormone antagonist in heifers     

Ginther OJ  Fuenzalida MJ  Pugliesi G  Hannan MA  Beg MA 《Domestic animal endocrinology》2011,40(2):119-127

Close temporality has been reported between the episodic secretion of luteinizing hormone (LH) and progesterone (P4) during the midluteal phase and preceding the beginning of luteolysis in cattle. In the present studies, the relationship between LH and P4 was examined by blocking LH oscillations with the gonadotropin-releasing hormone (GnRH) antagonist, acyline. In a titration study, the minimal single acyline dose for blocking LH oscillations in heifers was 3 μg/kg. The main experiment compared LH and P4 concentrations and oscillations between a group treated with acyline on day 15 after ovulation (n = 8) and a control group (n = 4). Concentrations of P4 in blood samples collected every 8 h on days 13 to 18 indicated that acyline treatment did not alter the time that luteolysis began or the length of the luteolytic process. In blood samples collected every hour for 24 h beginning at the hour of treatment, acyline reduced the LH concentrations and blocked LH oscillations. The hourly LH means were 0.06 to 0.08 ng/mL, comparable to the mean concentration at the nadirs of LH oscillations in controls (0.07 ng/mL). During the hourly sampling, the GnRH antagonist produced the following P4 responses: (1) lower P4 concentrations, (2) fewer and reduced prominence of P4 oscillations, and (3) increased length and variability in the interval between the peaks of P4 oscillations. Results indicated that LH oscillations affect both the prominence and the rhythmicity of P4 oscillations during preluteolysis but not the onset and length of luteolysis.  相似文献   

Gonadotropin-releasing hormone and gonadotropin in goldfish and masu salmon   总被引：1，自引：0，他引：1  

M. Kobayashi  M. Amano  M.H. Kim  Y. Yoshiura  Y.C. Sohn  H. Suetake  K. Aida 《Fish physiology and biochemistry》1997,17(1-6):1-8

Reproductive activities in vertebrates are regulated by an endocrine system, consisting of the brain-pituitary-gonad axis. In teleosts, gonadotropin-releasing hormone (GnRH) in the brain stimulates gonadotropin (GTH) release in the pituitary gland, but because of lack of the portal vessel, it is not known when and how much GnRH is released for the regulation of GTH release. There are multiple molecular types of GnRH in teleosts and several distinct populations of GnRH neurons in the brain. However, we do not know which types and populations of GnRH neurons regulate reproductive activities. Here we summarize our recent studies on GnRH and GTH in masu salmon Oncorhynchus masou and goldfish Carassius auratus. Immunocytochemistry showed the location and molecular types of GnRH neurons. Salmon (sGnRH) and chicken-II GnRH (cGnRH-II) neuronal fibers were widely distributed in the brain of both masu salmon and goldfish. Only sGnRH fibers were observed in the pituitary of masu salmon, whereas both sGnRH and cGnRH-II fibers were observed in the goldfish pituitary, indicating that species specific GnRH profiles are involved in the regulation of pituitary function in teleosts. A series of experiments in masu salmon and goldfish suggest that among GnRH neuron populations GnRH neurons in the ventral telencephalon and the hypothalamus regulate GTH release, and that GnRH of the terminal nerve origin is not essential to gonadal maturation and ovulation. The biological function of other GnRH neurons remains unkown. Two GTHs appear to be characteristic of teleost; however, regulation of reproduction by these GTHs is a question that remains to be elucidated. In salmonid species, it is proposed that GTH I stimulates early gonadal development, whereas GTH II acts in later stages. When GTH expression was examined in goldfish, both GTH I and II mRNA levels in the pituitary gland showed increases in accordance with gonadal development, unlike the sequential expression of GTH subunits in salmonids. The expression of these GTH subunit mRNAs were affected by water temperature, starvation, and steroid hormones in goldfish, but in what manner these two GTHs regulate gonadal development remains to be clarified.  相似文献   

细胞外Ca²⁺和K⁸对鲤鱼脑垂体离体生长激素分泌的影响   总被引：2，自引：1，他引：2       下载免费PDF全文

林信伟  林浩然 《水产学报》1993,17(1):07-13

采用脑垂体离体灌流孵育系统,研究细胞外 Ca~(2+)和 K~+对鲤鱼脑垂体基础的和鲑鱼促性腺激素释放激素(sGnRH)刺激的生长激素(GH)分泌的影响。离体灌流孵育的鲤鱼脑垂体基础 GH分泌和 sGnRH 刺激的 GH 分泌都是细胞外 Ca~(2+)依赖的,缺细胞外 Ca~(2+)存在时,基础 GR分泌显著下降,2分钟脉冲式 sGnRH 刺激的 GH 分泌反应接近消失。Ca~(2+)通道阻滞剂异搏定以剂量依存形式显著抑制基础的和2分钟脉冲式sGnRH 刺激的 GH 分泌,表明细胞外 Ca~(2+)的作用至少部分通过细胞膜电位敏感性 Ca~(2+)通道。50mM K~+显著刺激基础GH 分泌,并显著加强高剂量sGnRH 刺激的GH 分泌,且K~+的作用是细胞外 Ca~(2+)依赖的。  相似文献   

Distinct expression of GnRH genes in the red seabream brain   总被引：1，自引：0，他引：1  

K. Okuzawa  J. Granneman  J. Bogerd  H.J.Th. Goos  Y. Zohar  H. Kagawa 《Fish physiology and biochemistry》1997,17(1-6):71-79

This paper reports the molecular cloning of a cDNA encoding the precursor of seabream gonadotropin-releasing hormone (prepro-sbGnRH) and the localization of salmon GnRH (sGnRH) and seabream GnRH (sbGnRH) expressing neurons in the brain of the red seabream (Pagrus major). The cloned prepro-sbGnRH cDNA has a 285 bps open reading frame encoding a 23 amino acid signal peptide, a 10 amino acid sbGnRH, the cleavage site (Gly-Lys-Arg), and a 59 amino acid GnRH-associated peptide. The expression of sGnRH and sbGnRH peptides, and prepro-sGnRH and prepro-sbGnRH mRNA were studied using immunocytochemistry and non-radioactive in situ hybridization, respectively. We found cell bodies that reacted positively with both the sGnRH cRNA probe and anti-sGnRH serum, but not with the sbGnRH cRNA probe or anti-sbGnRH serum in the ganglion of the terminal nerve. Cell bodies that reacted positively with the sbGnRH cRNA probe, anti-sbGnRH serum, and anti-sGnRH serum, but negatively with the sGnRH cRNA probe were found in the preoptic area (POA). Immunocytochemistry showed that a distinct bundle of axons arises in the POA which projected to the pituitary gland. These results suggest that sbGnRH is the most relevant hypophysiotropic form of GnRH.  相似文献   

GnRH及其受体在2种真骨鱼消化系统中存在的免疫细胞化学证据     

方之平 《水产学报》2004,28(3):261-266

用链霉亲和素—生物素化过氧化物酶复合物(strept avidin biotin—peroxidase complex，SABC)免疫细胞化学方法，使用促性腺激素释放激素(gonadotropin—releasing hormone，GnRH)，促性腺激素释放激素受体(gonadotropinreleasing hormone receptor，GnRHR)2种抗血清对黄颡鱼(Pelteobagrus fulvidraco)和鲇(Silurus asotus)的食道、贲门、胃底、幽门、前肠、中肠、后肠和胰中的免疫活性内分泌细胞进行了定位。结果表明：在鲇的食道、胃、肠、肠固有膜、肠肌间神经丛、胰腺和胰岛中均存在着GnRH和GnRHR免疫活性阳性反应；黄颡鱼消化系统中除了在食道和胰岛中未见GnRH和GnRHR的免疫活性阳性反应外，其他部位均有阳性反应，而且GnRH和GnRHR分泌细胞的分布模式相类似。说明胃肠道中GnRH分泌细胞可能以自分泌或旁分泌方式参与消化功能的调节。本研究首次证实在鱼类的消化系统中存在着GnRH及其受体的免疫活性内分泌细胞，可为GnRH功能的多样性等研究领域提供新的形态学依据。  相似文献   

Immunohistochemical localization of three GnRH systems in brain and pituitary of Japanese flounder     

Ky Xuan Pham  Masafumi Amano  Noriko Amiya  Yutaka Kurita  Akio Shimizu  Kunio Yamamori 《Fisheries Science》2007,73(5):1113-1122

ABSTRACT:   To clarify the possible roles of gonadotropin-releasing hormone (GnRH) in the reproduction of Japanese flounder Paralichthys olivaceus , localization of salmon GnRH (sGnRH), chicken GnRH-II (cGnRH-II), and sea bream GnRH (sbGnRH) immunoreactive (ir) cell bodies and fibers in the brain and pituitary were examined together with follicle stimulating hormone (FSH) and luteinizing hormone (LH)-ir cells in the pituitary by immunohistochemistry. sGnRH-ir cell bodies were localized in the ventromedial part of the rostral olfactory bulb and cGnRH-II-ir cell bodies were restricted to the midbrain tegmentum, while sbGnRH-ir cell bodies were evident in the preoptic area. sGnRH-ir fibers were distributed throughout the brain, especially abundant in the forebrain. cGnRH-II-ir fibers were also scattered in many areas of the brain with abundance in the midbrain, but sbGnRH-ir fibers were observed in the preoptic–hypothalamic area and innervated the pituitary. In the pituitary, neither sGnRH-ir fibers nor cGnRH-II-ir fibers were found, but sbGnRH-ir fibers were profuse in the neurohypophysis and invaded the proximal pars distalis, targeting FSH and LH cells. These results suggest that three GnRH systems can play different physiological roles in the brain of Japanese flounder. Among them, sbGnRH is considered to be involved in reproduction by stimulating gonadotropin secretion, while sGnRH and cGnRH-II can function as a neurotransmitter and/or neuromodulator within the brain in this species.  相似文献   

Corals have already evolved the vertebrate-type hormone system in the sexual reproduction     

Wen-Hung Twan  Hua-Fang Wu  Jiang-Shiou Hwang  Yan-Horn Lee  Ching-Fong Chang 《Fish physiology and biochemistry》2005,31(2-3):111-115

Most broadcast spawning scleractinian corals synchronously release gametes during a brief annual spawning period. In southern Taiwan, the mass spawning of scleractinians occurs in lunar mid-March. Endocrine system has been proposed to play important roles in this annual phenomenon. A scleractinian coral, Euphyllia ancora has been selected as a model for the hormones and reproduction studies. We detected the presence of estradiol (E2), testosterone (T), glucuronided E2, glucuronided T, aromatase, immunoreactive (ir)GnRH in coral polyps E. ancora. Annual profiles of sex steroids, aromatase, and irGnRH have also been characterized. We found the parallel increases in irGnRH concentrations, aromatase activity and free E2 and glucuronided E2 concentrations at the time of coral mass spawning. The stimulation of mammalian (m)GnRH agonist in the increased aromatase activity and sex steroid concentrations was also observed in corals. Coral extracts (irGnRH) and mGnRH agonist had a similar dose-dependent effect on luteinizing hormone release in black porgy fish pituitary cells (in vitro). In conclusion, our data suggest that irGnRH and glucuronided E2 may play important roles in the control of reproduction and mass spawning in corals. Corals already evolved the vertebrate-type hormone system in the sexual reproduction.  相似文献   

Gonadotropin-releasing hormone in two perciform fishes: Micropogonias furnieri and Pagrus pagrus     

A.D. Montaner  L.A. Miranda  D. Vizziano  A. López  K. Okuzawa  G.M. Somoza 《Fish physiology and biochemistry》2001,24(3):243-246

Gonadotropin-releasing hormone (GnRH) molecular variants were characterized by gradient reverse phase high performance liquid chromatography (RP)-HPLC) from brain extracts of two perciforms with economic importance for Argentina and Uruguay. RP-HPLC fractions were tested in radioimmunoassays (RIAs) with both poly-specific and specific antisera. Both species showed the presence of the same three molecular forms, immunologically and chromatographically indistinguishable from sbGnRH, cGnRH-II and sGnRH. This study supports the hypothesis that their expression is a common pattern in perciforms.  相似文献