四种合成人抑制素α亚基片段对大鼠黄体细胞孕酮分泌的影响及与蛋白激酶A系统的关系

The effect of 4 synthetic human inhibin alpha fragments on progesterone production by rat corpus luteal cells and its relation to protein kinase A system

应用大鼠黄体细胞离体培养方法，观察４种人工合成人抑制素α亚基Ｎ末端片段：Ｐ￣(２２)（７～２８）、Ｐ￣(３２)（１～３２）、Ｐ￣(３２)－Ｔｙｒ（１～３２－Ｔｙｒ）和Ｐ￣(２９)（３７～６５）对基础孕酮及绒毛膜促性腺激素（（ｈＣＧ）和卵泡刺激素（ＦＳＨ）致孕酮分泌作用的影响。结果表明：（１）４种α片段（１００ｎｇ）均显著抑制大鼠黄体细胞的基础孕酮分泌。除Ｐ￣(２２)无抑制作用外，其余３种片段不同程度地减弱ｈＣＧ和ＦＳＨ刺激的孕酮分泌。（２）４种α片段也显著抑制Ｆｏｒｓｋｏｌｉｎ（１００ｎｍｏｌ／Ｌ）、ｄｂｃＡＭＰ（２０ｎｍｏｌ／Ｌ）及蛋白激酶Ａ（ＰＫＡ）（１０μｇ）刺激基础孕酮分泌效应。表明各α片段对ＰＫＡ系统从受体水平到ｃＡＭＰ环节，直到ＰＫＡ水平均有抑制作用，α片段抑制孕酮分泌与ＰＫＡ系统有关。

bjectives:To investigate the effects of 4 human inhibin(hIn)α fragments on basal hCG and FSH induced progesterone(P_4)production by rat corpus luteal(CL)cell;and the role of protein kinase A(PKA)signal system in their action.Design:An in vitro culture study.Setting:Reproductive Endocrinology Laboratory in Harbin Medical University.Methods:Superovulation and luteinization of the follicles were induced in immature(25～28day)Wistar rats by subcutaneous injection of 65IU PMSG,followed bv 35IU hCG.CL cells were dispersed by Collagenase-DNase and cultured in KRBGAL solution,4 in the medium were measured by RIA after 2 hrs incubation.Results:Four hIn α fragments,P￣(22),P￣(32),P￣(32)-Tyr,and p￣(29),were synthesized.The 4 hin a fragments all caused signifcant decrease in basal P_4.With the exception of p￣(22),the other three fragments at the dose of l00 ng all attenuated the FSH(0.02 IU)and hCG(0.2 IU)stimulated P_4.It was further shown that 4afragments all inhibited the P_4,stimulated by l00 nmol/L Forskolin,20 nmol/L dbcAMP,and l0μg PKA,significantly.Forskolin and FSH significantly stimulated P4 production,but Forskolin conbined with FSH caused inhibitory effect on P_4,and this action was enhanced by hIn α fragments Concl usion:The inhibitory action of hIn α on P_4 production by rat CL cells could possibly throughthe act on the receptor,cAMP and PKA level,resulting in reduction of progesterone.