促性腺激素释放激素在不同品种母牛垂体中的免疫组化定位

为了掌握促性腺激素释放激素（GnRH）及其受体在不同品种母牛垂体中的变化规律,采用免疫组化SP染色法分别对广西沼泽型水牛、摩拉杂交水牛、荷斯坦奶牛、广西本地黄牛垂体中GnRH的分布表达进行对比研究。结果表明,不同品种母牛垂体中均发现有呈棕黄色或黄褐色的GnRH阳性物质存在,经Image-Pro Plus 6.0软件统计发现,摩拉杂交母水牛的GnRH免疫阳性细胞较其他3个品种的大（P〈0.05）,而平均光密度值介于荷斯坦母奶牛和广西本地母黄牛之间（P〉0.05）。在神经垂体中仅发现GnRH免疫阳性纤维,而未发现GnRH免疫阳性细胞;在腺垂体远侧部的细胞均呈GnRH免疫反应阳性,阳性物质主要分布在腺垂体远侧部嫌色细胞和嗜色细胞胞质内。说明GnRH对腺垂体激素分泌的调节可能是直接通过神经调节,而神经垂体可能只是GnRH调节过程的通路。     

Hormonal regulation of gonadotropin receptors and steroidogenesis in cultured fetal rat tests

Gonadotropic activation of the adult rat testis in vitro and in vivo is followed by down-regulation of luteinizing hormone receptors and decreased androgen responses to subsequent hormonal stimulation. In contrast, treatment of cultured fetal testes with gonadotropins and dibutyryl adenosine 3',5'-monophosphate enhanced steroidogenic responsiveness and did not cause the luteinizing hormone-receptor loss and desensitization that is characteristic of the adult gonad. The analysis of gonadotropin receptors and action in cultured fetal testis cells facilitates developmental studies of gonadal function, and has revealed significant differences in the responses of fetal and adult Leydig cells to gonadotropic regulation.     

Primary structures of human pituitary growth hormone and sheep pituitary lactogenic hormone compared

The primary structures of human pituitary growth hormone and sheep pituitary lactogenic hormone have been compared with regard to similarities in their sequence. Three homologous segments in each molecule, comprising approximately 45 percent of either peptide chain, have been found. These two proteins have apparently evolved from a common ancestor molecule.     

促性腺激素释放激素在不同品种公牛睾丸中的免疫组化定位

为了掌握促性腺激素释放激素（GnRH）及其受体在不同品种公牛睾丸中的变化规律,采用免疫组化SP染色法分别对广西沼泽型水牛、摩拉杂交水牛、荷斯坦奶牛、广西本地黄牛睾丸中GnRH的分布表达进行对比研究。结果表明,不同品种公牛睾丸生精细胞和间质细胞中均有GnRH免疫阳性物质存在,经Image-Pro Plus 6.0软件统计发现,荷斯坦奶牛睾丸的GnRH阳性细胞个数最多、胞体最大,而广西本地黄牛睾丸的GnRH阳性细胞数量最少、胞体最小,说明GnRH在不同品种公牛睾丸的分布差异可能与生产性能有关,也提示GnRH在生殖调控中除能刺激垂体分泌FSH、LH外,可能直接与生殖器官发生作用,通过旁分泌、自分泌、神经分泌等多种方式调节蛋白类、多肽类激素的分泌及类固醇激素的产生,进而调节这些靶细胞和靶器官的功能活动。     

Thyroid hormone induction of an autocrine growth factor secreted by pituitary tumor cells

Thyroid hormones stimulate the rate of cell division by poorly understood mechanisms. The possibility that thyroid hormones increase cell growth by stimulating secretion of a growth factor was investigated. Thyroid hormones are nearly an absolute requirement for the division of GH4C1 rat pituitary tumor cells plated at low density. Conditioned media from cells grown with or without L-triiodothyronine (T3) were treated with an ion exchange resin to remove T3 and were tested for ability to stimulate the division of GH4C1 cells. Conditioned medium from T3-treated cells was as active as thyroid hormone at promoting GH4C1 cell growth but did not elicit other thyroid hormone responses, induction of growth hormone, and down-regulation of thyrotropin-releasing hormone receptors, as effectively as T3 did. A substance or substances associated with T3-induced growth stimulatory activity migrated at high molecular weight at neutral pH and was different from known growth-promoting hormones induced by T3. The results demonstrate that thyroid hormones stimulate the division of GH4C1 pituitary cells by stimulating the secretion of an autocrine growth factor.     

促性腺激素释放激素在不同品种水牛卵巢中的免疫组化定位

【目的】了解促性腺激释放激素（GnRH）在广西沼泽型水牛与摩拉杂交水牛卵巢中定位表达的异同点,为深入阐明GnRH调节卵巢功能的机制提供理论依据。【方法】采用免疫组化SP染色法对广西沼泽型水牛和摩拉杂交水牛卵巢中GnRH及其受体的分布表达进行对比研究。【结果】两种不同品种水牛卵巢中均存在大量的GnRH阳性细胞,且主要位于颗粒层细胞和黄体粒细胞的胞质内;通过比较显示,两种不同品种水牛卵巢GnRH阳性细胞个数差异极显著（P〈0．01）,但GnRH阳性细胞大小及其平均光密度的差异均不显著（P〉0．05）。【结论】不同品种水牛卵巢的GnRH分布差异可能与繁殖性能有关,但主要分布于巢卵颗粒层细胞和黄体粒细胞的胞质内。     

Antireproductive effects of a potent gonadotropin-releasing hormone antagonist in the male rat

Administration of a potent antagonist of gondadotropin-releasing hormone (GnRH) antagonist [Ac-dehydro-Pro1, pCl-D-Phe2, D-Trp3,6]-N alpha-MeLeu7-GnRH to adult male rats for 2 weeks resulted in decreased testosterone production and sexual organ weights and in disrupted spermatogenesis. The results demonstrate the essential role of gonadotropin-releasing hormone in the maintenance of reproductive functions and have implications for the regulation of male fertility.     

奥利亚罗非鱼促性腺激素释放激素cDNA的克隆及原核表达

促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)是下丘脑分泌产生的神经激素,对脊椎动物生殖的调控起重要作用。本研究通过RT-PCR方法从奥利亚罗非鱼丘脑中扩增出长约400 bp的目的序列GnRH,并将其克隆到T载体中,经酶切鉴定、序列测定分析后表明其与尼罗罗非鱼和乌颊海鲷具有较高的同源性,处于同一个进化分支上;而与日本青、金鱼、拟鲤、壁虎等的同源性较低。将此cDNA片段定向克隆到表达载体pMAL-c2x中构建重组表达质粒pMAL-GnRH,转化到大肠杆菌TB1中,0.3M IPTG诱导4 h后成功表达出与预期大小相符的约56 kD的融合蛋白。表明大肠杆菌表达系统可以成功地体外表达奥利亚罗非鱼GnRH,为进一步制备抗体了解其免疫调节作用奠定基础。     

奥利亚罗非鱼促性腺激素释放激素cDNA的克隆及原核表达

促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)是下丘脑分泌产生的神经激素,对脊椎动物生殖的调控起重要作用。本研究通过RT-PCR方法从奥利亚罗非鱼丘脑中扩增出长约400 bp的目的序列GnRH,并将其克隆到T载体中,经酶切鉴定、序列测定分析后表明其与尼罗罗非鱼和乌颊海鲷具有较高的同源性,处于同一个进化分支上;而与日本青、金鱼、拟鲤、壁虎等的同源性较低。将此cDNA片段定向克隆到表达载体pMAL-c2x中构建重组表达质粒pMAL-GnRH,转化到大肠杆菌TB1中,0.3M IPTG诱导4 h后成功表达出与预期大小相符的约56 kD的融合蛋白。表明大肠杆菌表达系统可以成功地体外表达奥利亚罗非鱼GnRH,为进一步制备抗体了解其免疫调节作用奠定基础。     

鸡胚垂体生长激素细胞的发生及其变化

为研究鸡胚垂体中生长激素细胞的发生及其在发育过程中的变化 ,分别在鸡胚发育的第 3 5～ 2 0 5天采集鸡胚垂体 ,用免疫组织化学方法研究鸡胚垂体中生长激素细胞的发生和细胞形态、数量、在垂体中的分布特点和在发育过程中的变化。结果表明 ,鸡胚发育中期第 9 5天可观察到少量的生长激素阳性细胞散在分布于垂体后叶 ,细胞多排列成索状或团状 ,细胞之间边界不清 ,细胞核较大。在鸡胚发育的第 12 5天以后 ,生长激素细胞的细胞浆与细胞核比值逐渐变小 ,且均匀分布于腺垂体的后叶。生长激素细胞数在鸡胚发育的第 12 5天之后显著升高 (P <0 0 1) ,在鸡胚发育的第 16 5天 ,生长激素细胞占垂体细胞总数的 9 4 %。以上结果证明鸡胚垂体中生长激素细胞增殖和分化过程主要发生在发育的中期至出壳之前 ,而生长激素细胞的分泌功能在鸡胚发育的后期最为活跃。     

An immunological investigation of human pituitary growth hormone

Growth hormone isolated from human pituitaries has been demonstrated to be a good antigen in the rabbit. With the rabbit antiserum to human somatotropin, it is possible to detect as little as 0.1 microg of the hormone by precipitin test. The antiserum was also capable of neutralizing the growth-promoting activity of human somatotropin.     

Gonadotropin-releasing hormone: regulation of adenosine 3',5'-monophosphate in ovarian granulosa cells

The antigonadal effects of gonadotropin-releasing hormone in ovarian granulosa cells are due to attenuation of the adenosine 3',5'-monophosphate (cyclic AMP) response to follicle-stimulating hormone. Agonists of gonadotropin-releasing hormone progressively inhibit adenylate cyclase and stimulate phosphodiesterase activities in cultured granulosa cells, indicating that blockade of gonadotropin action is attributable to the combined effects of decreased production and increased degradation of cyclic AMP.     

Male contraception; synergism of gonadotropin-releasing hormone analog and testosterone in suppressing gonadotropin

Long-term administration of either superactive analog's of gonadotropin-releasing hormone or of testosterone suppresses gonadotropin secretion in male animals and humans. Testosterone administered in combination with gonadotropin-releasing hormone analog further suppresses serum gonadotropin levels in male rats. This observation indicates synergistic activity and suggests that the gonadotropin-releasing hormone analog and testosterone act at independent sites within the hypothalamic-pituitary axis. The primary actions of superactive analog are probably mediated by changes at a postreceptor site in the pituitary gonadotropin-secreting cells.     

斑马鱼促性腺激素释放激素及相关肽基因的克隆与序列分析

从斑马鱼脑组织提取总RNA,应用RT-PCR方法克隆促性腺激素释放激素(GnRH) cDNA,其长度为646 bp,包括一个258 bp开放阅读框;编码的GnRH前体为86个氨基酸残基,由一个信号肽、GnRH十肽和一个由蛋白水解位点(Gly-Lys-Arg)连接的促性腺激素释放激素相关肽(GAP)组成;其中信号肽和相关肽的长度分别为24和49个氨基酸.该cDNA编码的GnRH的前体氨基酸序列与其他物种的GnRH前体基本一致.表明物种间GnRH cDNA的蛋白编码区高度保守,而非编码区的保守性程度很低.进化分析发现,斑马鱼与鲤、鲫、拟鲤、黑头软口鲦等淡水鲤科鱼类的同源性较高.     

N-甲基-D-天冬氨酸(NMDA)对肥育猪血清生长激素水平及腺垂体生长激素mRNA表达的影响

    选用60头体重60 kg左右杜长大三元杂交肥育猪,分为2组,分别饲喂0、100 mg·kg-1 N-甲基-D-天冬氨酸(NMDA),研究饲喂NMDA对肥育猪血清生长激素水平及腺垂体生长激素mRNA表达的影响.结果表明,试验43 d后,肥育猪血清生长激素水平显著提高,较对照组增加41.01%(P<0.05),其中阉公猪生长激素分泌总体水平增加36.91%(P<0.05).肥育母猪生长激素分泌总体水平提高45.95%(P<0.05);腺垂体生长激素mRNA丰度也显著提高,较对照组增加48.75%(P<0.05).由此可知,NMDA可以影响肥育猪血清生长激素分泌及腺垂体生长激素mRNA的表达,从而促进肥育猪生长.     

1 alpha, 25-Dihydroxyvitamin D3 nuclear receptors in pituitary

Specific binding of 1 alpha,25-dihydroxyvitamin D(3) was found in nuclear and cytosol fractions of the bovine pituitary. For nuclear binding. the dissociation constant was 0.1 namomole per liter, and maximum binding was 104 femtomoles per milligram of protein. In competition studies, 25-hydroxyvitamin D(3) was 300 times weaker than 1 alpha,25-dihydroxyvitamin D(3). The existence of high-affinity sites supports a physiologic role for 1 alpha,25-dihydroxyvitamin D(3) in the pituitary.