Purification and characterization of an FSH releasing protein from porcine ovarian follicular fluid

A variety of hypophysiotropic peptides or proteins have been reported to be present in mammalian gonads. Inhibin, a hormone that under most circumstances selectively suppresses the secretion of follicle-stimulating hormone (FSH) but not luteinizing hormone (LH), has been isolated from the gonadal fluids of several species and characterized as a heterodimeric protein consisting of alpha- and beta-polypeptides associated by disulphide bonds. The complete amino-acid sequences of the precursors of porcine and human inhibin alpha-subunits and two distinct porcine inhibin beta-subunits (beta A and beta B) have been deduced from complementary DNA sequences. Gonadotropin releasing peptides have also been found in the gonad and have generally been shown to be active in radioreceptor assays for gonadotropin releasing hormone (GnRH) but to exhibit different chromatographic and immunological characteristics from those of GnRH. During our purification of inhibin from porcine follicular fluid, we noted fractions that could stimulate the secretion of FSH by cultured anterior pituitary cells. We report here the purification of an FSH releasing protein (FRP) and its characterization by SDS-polyacrylamide gel electrophoresis under non-reducing and reducing conditions and by partial sequence analysis. Our results indicate that porcine gonadal FRP is a homodimer consisting of two inhibin beta A-chains linked by disulphide bonds. FRP is highly potent (50% effective concentration (EC50) approximately 25 pM) in stimulating the secretion and biosynthesis of FSH but not of LH or any other pituitary hormone. In contrast to the effects of GnRH and other reported gonadal gonadotropin releasing fractions, the action of FRP is not mediated by GnRH receptors.     

Lactogenic receptor regulation in hormone-stimulated steroidogenic cells

Receptor sites for lactogenic hormones such as prolactin (PRL), human growth hormone (HGH), and placental lactogens, are widely distributed in mammalian tissues, including mammary glands, steroid-secreting cells of the adrenal, testis, and ovary, and target cells of steroid hormone action such as liver, prostrate, and kidney. Although the biological functions of lactogen binding sites remain uncertain, a relationship between prolactin and lipoprotein metabolism is implied by the occurrence of prolactin receptors in steroidogenic cells of the gonads and adrenal, and by the ability of prolactin to increase esterified cholesterol in the testis. Recently, loss of testicular prolactin receptors has been observed following elevation of circulating luteinising hormone (LH) concentrations by the gonadotropin releasing hormone (GnRH) and its agonist analogues. The hormone dependence of lactogen receptor sites in steroid-secreting cells was further analysed in rat testis, ovary, and adrenal glands after treatment with the respective trophic hormones, gonadotropin and ACTH. In each of these tissues, rapid and transient loss of lactogen receptors was observed after trophic hormone stimulation. These findings indicate that increased turnover of lactogen receptors is an important component of the target-cell response, and suggest that prolactin receptors might be involved in the transport of lipoprotein precursors for steroid biosynthesis.     

Role of plasminogen activator and plasminogen activator inhibitor type-1 in luteolysis——a minireview

This minireview summarized our recent studies on the role of plasminogen activator (PA) and inhibitor type-1 (PAI-1) in luteolysis. We have demonstrated that (1) both tissue type and urokinase type plasminogen activators (tPA and uPA) and a plasminogen activator inhibitor type-1 (PAI-1) were present in the corpus luteum of rat and rhesus monkey; (2) decrease in progesterone production in corpus luteum was well correlated with a sharp increase in tPA (but not uPA) and PAI-1 secretion; (3) exogenous tPA decreased luteal progesterone synthesis while monoclonal antibodies increased progesterone production; (4) interferon y inhibited luteal progesterone synthesis and stimulated tPA production while LH plus pro-lactin increased progesterone production and decreased tPA (but not uPA) activity in cultured luteal cells; (5) increase in proteolysis in the corpus luteum was also correlated with decrease in progesterone production in mouse. These data suggest that local degradation of extracellular matrix controlled by plasminogen activator and inhibitor is involved in the processes of luteolysis.     

Role of plasminogen activator and plasminogen activator inhibitor type-1 in luteolysis—a minireview

This minireview summarized our recent studies on the role of plasminogen activator (PA) and inhibitor type-1 (PAI-1) in luteolysis. We have demonstrated that (1) both tissue type and urokinase type plasminogen activators (tPA and uPA) and a plasminogen activator inhibitor type-1 (PAI-1) were present in the corpus luteum of rat and rhesus monkey; (2) decrease in progesterone production in corpus luteum was well correlated with a sharp increase in tPA (but not uPA) and PAI-1 secretion; (3) exogenous tPA decreased luteal progesterone synthesis while monoclonal antibodies increased progesterone production; (4) interferony inhibited luteal progesterone synthesis and stimulated tPA production while LH plus prolactin increased progesterone production and decreased tPA (hut not uPA) activity in cultured luteal cells; (5) increase in proteolysis in the corpus luteum was also correlated with decrease in progesterone production in mouse. These data suggest that local degradation of extracellular matrix controlled by plasminogen activator and inhibitor is involved in the processes of luteolysis.     

Follicles in pregnant rat ovary are incapable of steroidogenesis

Antral follicles are present in the ovaries throughout gestation. These follicles are “physically immature” and cannot ovulate under the induction of LH/hCG. The purpose of the present study is to examine whether follicles in pregnant rat ovaries are capable of steroidogenesis. StAR is believed to be the key regulator of steroid hormone biosynthesis. Antisense StAR probe and anti-StAR rabbit serum have been used to detect the StAR expression in ovarian follicles at various stages of pregnant rats. The results indicate that theca-interstitial cells and the membrane granulosa cells at the stages from the estrous or pre-estrous in the normal cycling rat ovary express StAR mRNA and its protein, whereas neither granulosa cells nor the theca cells in pregnant ovary throughout gestation express StAR. These results indicate that the pregnant follicles throughout gestation are incapable of steroidogenesis.     

过表达 miRNA-320 对顺铂诱导卵巢早衰大鼠卵巢功能的影响

摘要:目的 探讨过表达 miRNA-320 对顺铂诱导卵巢早衰大鼠卵巢功能的影响。 方法 选择清洁级 SD 雌性大鼠32 只,随机分为 4 组:正常对照组、模型组、阴性对照组和 miRNA-320 过表达组,每组 8 只。 在实验过程中,每天观察各组大鼠饮食、活动和体毛等外在表现的差异。 采用 ELISA 检测各组大鼠血清中 E2、FSH、LH 的含量;采用 HE染色,光镜下观察各组大鼠卵巢组织形态学变化;采用 PCR 检测各组大鼠卵巢组织 miRNA-320、PGRMC1、BMP15的表达水平;采用 Western blot 检测各组大鼠卵巢组织中 PGRMC1、BMP15 的蛋白表达水平。 结果 与正常对照组相比,模型组大鼠活动迟缓、无精神、反应迟钝、食欲下降、体质量下降以及体毛暗淡无光泽;组织形态学分析表明,卵巢组织明显萎缩、皮质变薄、闭锁卵泡数目多以及间质纤维组织增多;血清 FSH、LH 显著升高,而血清 E2 及卵巢组织中 PGRMC1、BMP15 的蛋白和 mRNA 表达水平均降低,差异具有统计学意义( P< 0. 05) 。 与阴性对照组相比,miRNA-320 过表达组大鼠活动量增加、反应较为敏捷、进食增多、体毛逐渐有光泽;间质纤维化明显减轻、成熟卵泡数量明显增加、黄体数增多;血清 E2 的含量、卵巢组织中 PGRMC1、BMP15 的蛋白和 mRNA 的表达水平均升高,而FSH、LH 的含量降低( P<0. 05) 。 结论 顺铂可诱导卵巢早衰大鼠卵巢功能障碍,过表达 miRNA-320 可改善顺铂诱导的卵巢早衰大鼠的卵巢功能。     

Interferon-like sequence of ovine trophoblast protein secreted by embryonic trophectoderm

In most species the length of a pregnancy exceeds that of the luteal phase of the ovarian cycle. The conceptus within the uterus, therefore, is believed to produce a substance or substances which directly or indirectly prolong the lifespan of the corpus luteum and prevent a return to ovarian cyclicity. This phenomenon is known as maternal recognition of pregnancy. The active substance implicated in signalling maternal recognition of pregnancy in the sheep is an embryonic secretory protein, known as ovine trophoblast protein-1 (oTP-1) (refs 2-4), which is targeted in a paracrine manner to the uterine epithelium of the mother. We report here the primary amino-acid sequence of oTP-1 as inferred from a cloned complementary DNA and demonstrate that the protein is most probably an interferon-alpha.     

Regulation of ovarian function by the matrix metalloproteinase system

In most organs of mammals, cyclic remodelling of tissues after morphogenesis is minimal; however, repro-ductive tissues of female animals including endometrium, mammary gland, ovarian follicle and corpus luteum un-dergo growth, maturation and involution at various stages in the reproductive cycle or lifespan of the animal. Recon-struction of the extracellular matrix (ECM) is required for the dynamic tissue reorganization characteristic of these tissues. The ECM consists of proteinaceous and nonpro-teinaceous molecules that provide the tissue-specific, ex-tracellular architecture to which cells attach. Furthermore, interaction of cellular receptors with proteins of the ECM can regulate cellular structure, second messenger genera-tion and gene expression. Maintenance of ECM homeo-stasis depends largely on coordinated action of matrix metalloproteinases (MMPs) and tissue inhibitors of met-alloproteinases (TIMPs)-- an important proteinase sys-tem responsible for degradating and remodelling of ECM[1]. MMPs/TIMPs have been recognized as the cru-cial role players in regulating follicular and luteal function for their extensive involvements in the cyclic changes of dynamic ovarian tissues. In recent years, literature that MMP system has important roles in ovary is accumulating. The focus of this review is on the effects of MMPs and their inhibitors, TIMPs on follicular growth, atresia, ovu-lation, luteal development, and luteolysis. Emphasis has been given to the recent progress in the new field when-ever possible.     

脊椎动物促性腺激素释放激素的结构、基因表达与调控的研究进展

综述了有关对脊椎动物促性腺激素释放激素的结构、基因表达与调控的研究进展 .阐明促性腺激素释放激素结构多样性 ,功能多样性 ,及其基因表达与调控 ,并对可能的应用前景作简要阐述     

促孕散治疗奶牛卵巢疾病引起不孕症的研究

本研究用促孕散对奶牛持久黄体和卵巢静止进行分组治疗，并与激素治疗作对比。结果表明，促孕散治疗持久黄体试验牛发情有效率为97．62％，配种受胎率为90．24％；促孕散治疗卵巢静止试验牛发情有效率为92．59％，配种受胎率为92．0％；经氯前列烯醇治疗持久黄体试验牛的配种受胎率为71．11％，经绒毛膜促性腺激素治疗卵巢静止试验牛的配种受胎率为58．33％。由此说明，促孕散在治疗奶牛持久黄体和卵巢静止性不孕症中效果显著。     

GnRH-A抗原主动免疫雄兔对血液Fe、Cu、Zn的影响

目的:探讨促性腺激素释放激素类似物-A(GnRH-A)主动免疫时动物血液微量元素的变化规律,为深入研究GnRH免疫去势的作用机理提供科学依据.方法:用自制的GnRH-A抗原乳剂1.0 mL对兔子进行皮下注射,美国热电SOLAAR S4型原子吸收光谱仪测定Fe、Cu、Zn.结果:Zn的含量在第4周明显高于免疫去势前的水平(P<0.05),Cu和Fe与免疫去势前无显著差异(P>0.05).结论:GnRH-A主动免疫对雄兔血液微量元素无明显影响.     

Growth of human breast cancer cells inhibited by a luteinizing hormone-releasing hormone agonist

About one-third of human breast cancers require hormones for their continued growth and endocrine ablation or anti-hormone therapy can cause regression of these tumours. As a consequence, ovariectomy in premenopausal women or administration of an anti-oestrogen (tamoxifen) in postmenopausal women represent major options for treatment of metastatic breast cancer. Alternatively, chronic administration of agonistic analogues of luteinizing hormone-releasing hormone (LHRH) causes regression of mammary tumours in experimental animals, and such treatment has shown promise in a small series of premenopausal women with advanced breast cancer. It has been assumed that these results were achieved by suppressing the pituitary-ovarian axis, as the treatment causes a reduction in circulating levels of gonadal steroids similar to that produced by castration. However, LHRH agonists can exert major effects on tissues other than the pituitary in animals and in the human. Such findings, coupled with reports of LHRH in human breast milk and immunohistochemical evidence for the presence of LHRH-like activity in some human breast tumours, prompted us to test whether LHRH agonists could have direct antitumour effects. We now report major direct effects of LHRH and its agonists on the growth of breast tumour cells in culture.     

Discrete cis-active genomic sequences dictate the pituitary cell type-specific expression of rat prolactin and growth hormone genes

The anterior pituitary gland, which is derived from a common primordium originating in Rathke's pouch, contains phenotypically distinct cell types, each of which express discrete trophic hormones: adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), prolactin, growth hormone, and follicle stimulating hormone (FSH)/luteinizing hormone (LH). The structurally related prolactin and growth hormone genes, which are evolutionarily derived from a single primordial gene, are expressed in discrete cell types--lactotrophs and somatotrophs, respectively--with their expression virtually limited to the pituitary gland. The pituitary hormones exhibit a temporal pattern of developmental expression with rat growth hormone and prolactin characteristically being the last hormones expressed. The reported co-expression of these two structurally related neuroendocrine genes within single cells prior to the appearance of mature lactotrophs, in a subpopulation of mature anterior pituitary cells, and in many pituitary adenomas raises the possibility that the prolactin and growth hormone genes are developmentally controlled by a common factor(s). We now report the identification and characterization of nucleotide sequences in the 5'-flanking regions of the rat prolactin and growth hormone genes, respectively, which act in a position- and orientation-independent fashion to transfer cell-specific expression to heterologous genes. At least one putative trans-acting factor required for the growth hormone genomic sequence to exert its effects is apparently different from those modulating the corresponding enhancer element(s) of the prolactin gene because a pituitary 'lactotroph' cell line producing prolactin but not growth hormone selectively fails to express fusion genes containing the growth hormone enhancer sequence.     

虎纹蛙促性腺激素及其释放激素含量的日变化

利用具有高度特异性的放射免疫测定法,研究了10月份虎纹蛙成蛙脑和脑垂体GnRH、以及脑垂体和血浆GtH含量的日变化,结果表明：雌蛙脑和脑垂体mGnRH含量、以及脑垂体cGnRH-Ⅱ含量都存在有明显的日变化;雄蛙脑垂体和血浆LH水平,以及雌、雄蛙血浆FSH水平也都存在明显的日变化;对各种激素日变化产生的原因进行了探讨.     

Binding sites for growth hormone releasing factor on rat anterior pituitary cells

Growth hormone releasing factors (GRFs) have been isolated from human pancreatic tumours (hGRF) and rat hypothalamus (rhGRF). The response to GRF at the pituitary level can be modulated by other factors, including glucocorticoids, thyroid hormones, somatostatin and other neuropeptides and somatomedins. Glucocorticoids enhance GRF-induced growth hormone (GH) secretion in primary cultures of rat anterior pituitary cells, and the synthetic glucocorticoid dexamethasone has recently been shown to increase the amounts of GH released in freely moving rats in response to submaximal doses of intravenous GRF. To investigate whether somatotroph sensitivity to GRF is modulated at its receptor level, we have developed a radioreceptor assay using an iodinated analogue of hGRF as radioligand. We report here that the relative binding affinities of rGRF, hGRF and the two analogues are correlated with their in vitro biological potencies. Further, the number of GRF binding sites is drastically decreased in cells deprived of glucocorticoids either in vivo or in vitro.     

Changes in hypothalamic preproenkephalin A mRNA following stress and opiate withdrawal

The median eminence of the pituitary is rich in opioid receptors, and exogenous opioids have major effects on the release of adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), prolactin, growth hormone (GH) and thyrotropin. Stress results in similar changes in anterior pituitary hormone secretion. Enkephalin immunoreactivity has been reported in the medial parvocellular neurons of the hypothalamic paraventricular nucleus which project to the median eminence, the site where hypothalamic releasing factors are secreted into the portal blood and thence to the anterior pituitary gland. The endocrine response to stressful stimuli might therefore, at least in part, be mediated through the activation of hypothalamic enkephalinergic neurons. We show that two stressful stimuli, opiate withdrawal and intraperitoneal injection of hypertonic saline, both result in very rapid and marked increases in enkephalin mRNA in the parvocellular paraventricular nucleus. The activation of hypothalamic enkephalin neurons may be important in the neuroendocrine response to stress.     

钙调素特异性拮抗剂(TFP)对大鼠着床的影响

在大鼠孕４ｄ宫腔内一次性注入钙调素特异性拮抗剂－三氟拉嗪,每侧子宫角０．０５ｍＬ,具有显著的抗着床作用,抗着床率高达１００％,而注入等容量生理盐水的对照组为０％。     

Localization and expression of LHβmRNA in the brain and Hatschek's pit of amphioxus, Branchiostoma belcheri

To determine whether gonadotropin-like substance in the brain and Hatschek' s pit of amphioxus issynthesized by the tissue in situ or transported from other tissue, a histochemical study was carried out by in situ hy- bridization using digoxigenin (DIG)-labelled LHβRNAprobes. The results showed that LHβmRNA expressed in the nerve cells of brain and the epithelial cells of Hatschek' s pit, thus providing new evidence for the homology of pituitary of ver- tebrates with Hatschek' s pit and the functional evolution of gonadotropin.     

Zoological origin of gonadotropin subunits and association kinetics

Mammalian luteinizing hormone (LH) is an association of two dissimilar subunits, alpha and beta. In vitro studies, mainly using difference spectrophotometry, had shown that this phenomenon was slow, especially at low temperatures. If the situation was the same in poikiloterms, it would probably make gonadotropin (GTH) synthesis difficult for these animals in a cold environment. We have found that the formation of a teleost gonadotropin is in fact strikingly more rapid and less thermodependent than formation of mammalian LH. Also, studies with a fish-mammal hybrid molecule have allowed us to estimate the respective influence of the alpha and beta subunits in determining these differences.     

调内消癖丸药效学试验

目的观察调内消癖丸的功能主治,探讨调内消癖丸对大鼠实验性雌激素水平增高和对大鼠乳腺组织增生的影响。方法采用雌激素药物诱导大鼠乳腺组织增生模型的试验方法。结果调内消癖丸对大鼠乳腺组织有促进增长,并能调节黄体和卵巢功能(P<0.05,P<0.01P)。结论调内消癖丸有雄激素样作用,为临床用药提供依据。