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In teleosts, as in other vertebrates, the secretion of pituitary gonadotropin (GTH) is mediated by the hypothalamic decapeptide, gonadotropin-releasing hormone (GnRH). Recent findings in teleosts indicate that GnRH receptors are not restricted to the pituitary gonadotropes and are also associated with somatotropes as well as being present in a number of other tissues. In the present study, we provide novel information on GnRH binding in a number of extrapituitary tissues in goldfish. However, we do not intend to provide full characterization of GnRH binding sites in various extrapituitary tissues in goldfish as this would clearly be outside the scope of this paper. In this study we examined GnRH binding in a number of extrapituitary tissues in goldfish and observed specific binding in ovary, testis, brain, liver and kidney. No specific GnRH binding was observed in muscle, skin, gut, gill and heart. In general, the present findings together with the results of other studies carried out in our laboratory demonstrate that mature goldfish ovary and testis contain two classes of GnRH binding sites, high affinity/low capacity and low affinity/high capacity sites with binding characteristics similar to those of the pituitary GnRH receptors. The brain of goldfish was also found to contain two classes of GnRH binding sites, a super-high affinity/low capacity and a low affinity/high capacity sites. Furthermore, study of goldfish liver and kidney demonstrated the presence of a single class of GnRH binding sites with characteristics different from those of pituitary, ovary, testis and brain. Overall, it is evident that goldfish contains a family of GnRH binding sites which can be classified into four groups based on binding affinities: 1) A class of high affinity binding sites present in the pituitary, ovary and testis, 2) a class of super high affinity sites so far only detected in the brain, 3) a class of intermediate-affinity GnRH binding sites in the liver and kidney, and 4) a class of low affinity binding sites present in all the tissues containing specific GnRH binding sites except for liver and kidney. 相似文献
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此文对促黄体激素释放激素及其受体的结构、分布、功能以及研究现状进行了阐述,归纳了促黄体激素释放激素的主要功能。促黄体激素释放激素的结构和分布特点对于进一步研究促黄体激素释放激素及其类似物抑制肿瘤、导向传递药物治疗癌症方面有重要的意义。 相似文献
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Sadia Nazir Noor Khan Hamda Azmat Saima Naveed Malik Muhammad Ramzan Simon J. Davies 《Journal of the World Aquaculture Society》2023,54(1):143-155
A study was conducted to determine the artificial breeding response, embryonic and larval development of giant snakehead, Channa marulius, with the application of various dosages of stimulatory hormones: Suprefact® (LHRH) agonist and Ovaprim® (GnRH + dopamine inhibitor). First and second hormonal dosages of Suprefact® (diluted) and Ovaprim® (0.3, 0.4, and 0.5 ml for male and 0.8, 0.9, and 1.0 ml for females per kilogram body weight) were used. There were three treatments T1, T2, and T3 and each treatment had three replicates. Male fish were treated with T1 (0.3), T2 (0.4), T3 (0.5) ml kg−1 of body weight while female fish with T1 (0.8), T2 (0.9), T3 (1.0) ml kg−1 of body weight. The results showed that fish stimulated with T3 (1.0) obtained better fecundity rate (2951.7) followed by T2 (0.4) (2678.3), while the lowest fecundity (466.7) was recorded in T1. The numerically higher values of gonado-somatic index (males and females) and fertilization rate appeared in T2. The highest survival rate (97.1%) was found in T3 followed by T2 (97.0%), while the lowest (32.2%) in T1. In conclusion, the application of Suprefact® and Ovaprim® at 0.4 and 0.5 ml kg−1 body weight for male and 0.9 and 1.0 ml kg−1 for female fish successfully stimulated snakehead fish induced breeding. 相似文献
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通过催产试验,在高活性促性腺激素类似物相互之间、在类似物与ＨＣＧ之间、在类似物同ＨＣＧ或ＨＷＨＯ复配而成的复配制剂相互之间、在类似物与其复配制剂之间,进行了催产效果的对比。结果表明,各种类似物对不同鱼类的催产效果各不相同;类似物的催产效果明显优于ＨＣＧ;使用类似物复配制剂,其催产效果优于单独使用ＨＣＧ或类似物。 相似文献
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通过PCR方法,从肠出血性大肠杆菌O157:H7的基因组DNA中扩增出Stx1A基因序列,并将之与编码LHRH的基因序列连接起来,构建编码Stx1A-LHRH的重组融合基因片段,并定向克隆到表达质粒pET28a的NcoⅠ和EcoRⅠ位点之间,构建重组表达质粒pET28a::stx1A-LHRH,将重组质粒转化到宿主菌BL21(DE3)中。对重组菌株用IPTG进行诱导表达。SDS-PAGE电泳检测结果表明重组菌株表达出了23700的目的融合蛋白Stx1A-LHRH,目的蛋白为包涵体表达,经薄层扫描分析表明表达量约占菌体总蛋白的37.6%。为了将来更好的进行目的蛋白的功能研究,本研究再将融合基因片段克隆到表达质粒pMAL-p2x中实现了重组蛋白的可溶性表达,表达的重组蛋白经amylose亲和层析柱一步纯化后纯度可达93.4%,为下一步进行重组蛋白的活性分析及其生物学作用研究奠定了基础。 相似文献
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将１６只发情周期正常的母山羊随机分成３组：吗啡（Ｍｏｒ）组、纳洛酮（Ｎａｌ）组和对照（Ｃｏｎ）组，分别注射阿片受体兴奋剂Ｍｏｒ、阿片受体拮抗剂Ｎａｌ和等量生理盐水。通过收集垂体门脉血样，监测注射前后促黄体激素释放激素（ＬＨＲＨ）的变化。结果表明，在山羊中黄体期和早卵泡期注射Ｍｏｒ均能显著抑制丘脑下部ＬＨＲＨ的分泌（Ｐ＜０．０５），而注射Ｎａｌ则促进其分泌（Ｐ＜０．０５），在中黄体期注射比在早卵泡期注射效果更为明显。因而认为，在山羊，体内类阿片肽参与生殖内分泌的调节，它们可能参与丘脑下部—垂体—卵巢轴，通过卵巢类固醇的负反馈机理抑制丘脑下部ＬＨＲＨ的分泌。 相似文献
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Three molecular species of gonadotropin releasing hormone (GnRH) mRNA-containing neuronal populations (terminal nerve: salmon-GnRH; preoptic area: seabream-GnRH; midbrain: chic- ken-GnRH-II) have been localized in teleosts. While the termi- nal nerve GnRH neurons originate from the olfactory placode, a separate intracerebral source of origin for preoptic and midbrain neurons is possible. The preoptic GnRH neurons are regulated by gonadal steroids and gonadal maturation, however, the regulation and role of terminal nerve and midbrain GnRH neurons in teleosts reproduction is speculative and debatable. 相似文献
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本文应用免疫组化ABC法来研究三头成年雌性奶山羊的LHRH核周的及其神经纤维在下丘脑及隔区的分布。结果表明:LHRH核周体形态不规则,有突起,胞体和胞突内充满棕黑色的免疫反应颗粒。核周体主要分布在;(1)嗅脑隔区内由隔三角核、隔内侧核、视前正中核、视前内侧核、视前外侧核、斜角带核、前联合核构成的一条背腹走向的疏松细胞带。(2)由视前交叉上核、视前室周核、视上核、腹内侧核、腹外侧核、弓状核构成的一条斜向于正中隆起的细胞带。每头羊在以上两个细胞带内可查到112～173个LHRH核周体。 LHRH神经纤维呈明显的串珠状,长短与粗细均不一致,除了在上述各核团内有不同程度的分布外,还在正中隆起、血管终板器、灰结节、第三脑室室周均有较多的分布。此外在血管和脑室附近还可见到神经纤维终枝的分布。 相似文献