Functional participation in endocrine system : activin-follistsatin interaction

利用合成多肽抗体，采用免疫组化方法研究了抑制素/激活素β a亚基在大鼠睾丸中的定位。与- β - a抗体的强烈反应在细胞质中表现出来，而在细胞核和质膜中表现出来。尽管两种细胞的免疫染色模式不同，但在精子细胞质中也发现了这种反应；精母细胞中的颗粒状细胞和精细胞中的弥散状细胞。此外，质膜在精细胞中呈阳性，表明β - aa亚基可能在精细胞期产生，并从精细胞期分泌。这些结果表明抑制素或激活素可能在精子发生中起重要作用。研究了大鼠卵巢卵泡抑素定位的周期性变化及促性腺激素初生高潮在调节卵泡抑素表达中的作用。利用针对人卵泡抑素合成肽的多克隆抗体，采用免疫组化方法在成熟卵泡继发卵泡上皮细胞中检测到免疫反应性卵泡抑素。成熟卵泡颗粒细胞与抗卵泡素（123-134）的颗粒样反应在发情前的晚上急剧减弱。在发情1330h注射戊巴比酮（40mg /kg）阻断初级促性腺激素激增，导致在发情2300h成熟卵泡中维持卵泡素颗粒。通过在发情前1530h给戊巴比酮治疗的动物注射外源性LH（20马克）或FSH（10马克）来分解卵泡抑素的维持。这些结果表明，促卵泡素在排卵前卵泡中的表达受到原发性促性腺激素激增的抑制。卵泡抑素在排卵前卵泡中的剧烈变化表明，卵泡抑素在排卵前的积云扩张和生发囊破裂等生理现象中起着重要作用。我们首先用RT-PCR检测了大鼠胰岛中卵泡抑素和抑制素/激活素三个亚基的mRNA表达。免疫组化抗卵泡抑素血清显示卵泡抑素仅局限于产生胰岛素的B细胞。虽然在胰岛中检测到β aa亚基，但两种β aa抗血清的免疫染色细胞类型完全不同，即抗β aa (1-10)-Tyr染色的B细胞和抗β aa（87-99）染色的产生胰高血糖素的A细胞。这种不一致的免疫反应性可能与卵泡抑素与抑制素/激活素亚基的结合有关。本研究表明，胰岛的卵泡抑素和抑制素/激活素在内分泌胰腺中起副分泌或自分泌调节剂的作用。少

The localization ob betaA subunit of inhibin/activin in rat testis was studied by means of immunohistochemistry using antibody raised against synthetic polypeptides. The intense reaction with and-betaA antibody was shown in the cytoplasm but not in the nucleus and the plasma membrane of late pachytene spermatocytes. The reaction was also found in the cytoplasm of spermatids, although the immunostaining pattern was different between the two cells ; the granule-like one in spermatocytes and diffused one in spermatids, respectively. Furthermore, the plasma membrane became positive in spermatids, suggesting that betaA subunit may be produced in spermatocytes phase and secreted from spermatids phase. These results suggest that inhibin or activin may have a significant role in spermatogenesis.Cyclic changes in follistatin localization and the role of primary gonadotropin surges in regulating follistatin expression were studied in rat ovary. Immunoreactive follistatin was detected in the gran … More ulosa cells of secondary to mature follicles by immunohistochemistry using polyclonal antibodies raised against synthetic peptides of human follistatin. Granule-like reactions with Anti-follistatin (123-134) in the granulosa cells of mature follicles drastically decreased their intensity on the evening of proestrus. The blockade of primary gonadotropin surges by injection of pentobarbitone (40 mg/kg) at 1330h on proestrus, resulted in sustaining the follistatin granules in mature follicles at 2300h on proestrus. The sustainment of follistatin was broken down by injection of exogenous LH (20 mug) or FSH (10 mug) to pentobarbitone-treated animals at 1530h on proestrus. These results indicate that expression of follistatin in preovulatory follicles is suppressed by primary gonadotropin surge on proestrus. These drastic changes in follistatin in the preovulatory follicles suggest that follistatin plays a significant role in some physiological phenomena such as cumulus expansion and germinal vesicle break down prior to ovulation.We first detected the mRNA expression of follistatin and three subunits of inhibin/activin in rat pancreatic islets by RT-PCR.Immunohistochemistry using anti-follistatin serum revealed that follistatin was localized only in insulin producing B cells. Although the betaA subunit was detectable in the islets, the immunostainable cell type were completely different with two betaA antisera, i.e.anti-betaA (1-10)-Tyr stained B cells, while anti-betaA (87-99) stained glucagon producing A cells. This inconsistent immunoreactivity was probably related to follistatin binding to subunits of inhibin/activin. This study indicates that follistatin and inhibin/activin in the islet serve as paracrine or autocrine modulators in the endocrine pancreas. Less