Activation induced by luteinizing hormone of type II protein kinase dependent on cyclic adenosine monophosphate and phosphorylation of soluble proteins in porcine granulosa cells.
Activation induced by luteinizing hormone of type II protein kinase dependent on cyclic adenosine monophosphate and phosphorylation of soluble proteins in porcine granulosa cells.
复制标题
II 型蛋白激酶黄体生成素诱导的激活依赖于猪颗粒细胞中的环磷酸腺苷和可溶性蛋白的磷酸化。
作者：
D. H. Halpren;R. Jungmann;W. George;J. R. Jeter
本实验旨在研究外源性黄体生成素是否能在完整的猪颗粒细胞中诱导急性环磷酸腺苷(CAMP)介导的环磷酸腺苷依赖的蛋白激酶的激活和细胞蛋白的磷酸化。猪颗粒细胞(直径3~5 mm的卵泡)与2微克/毫升黄体生成素(L H)孵育后，2分钟内细胞环磷酸腺苷(CAMP)含量显著升高。黄体生成素还引起猪颗粒细胞II型环磷酸腺苷依赖性蛋白激酶同工酶的解离，呈时间和剂量依赖性。促黄体生成素(0.05-2微克/毫升)在刺激后2-30分钟显著解离依赖于环磷酸腺苷的蛋白激酶。蛋白激酶解离是促黄体生成素的特异效应，不能被促肾上腺皮质激素或催乳素引起。在黄体生成素诱导的蛋白激酶激活期，几种分子量在43000到99000之间的可溶性颗粒细胞蛋白以时间依赖性和激素特异性的方式被磷酸化。这些结果表明，环磷酸腺苷介导的颗粒细胞II型环磷酸腺苷依赖蛋白激酶的激活可能是黄体生成素短期分子作用的先决条件，从而导致几种功能未知的可溶性颗粒细胞蛋白的黄体生成素特异性磷酸化。
The present experiments were designed to study whether exogenous LH could elicit acute cyclic AMP-mediated activation of cyclic AMP-dependent protein kinase and phosphorylation of cellular protein in intact porcine granulosa cells. Incubation of porcine granulosa cells (from 3 to 5 mm diameter follicles) with 2 microgram luteinizing hormone/ml (LH) caused a significant rise of cellular cyclic AMP content within 2 min of the addition of LH. The increase was dose-dependent and occurred between doses of 0.2 and 2.0 microgram LH/ml. Luteinizing hormone also caused a time- and dose-dependent dissociation of the type II cyclic AMP-dependent protein kinase isozyme in porcine granulosa cells. Luteinizing hormone (0.05--2 microgram/ml) significantly dissociated the cyclic AMP-dependent protein kinase between 2 and 30 min after stimulation. The protein kinase dissociation was a specific effect of LH and was not elicited by either adrenocorticotrophic hormone or prolactin. During the period of LH-induced protein kinase activation, several soluble granulosa cell proteins, ranging in molecular weights from about 43 000 to 99 000, became phosphorylated in a time-dpeendent and hormone-specific manner. The results suggest that cyclic AMP-mediated activation of granulosa cell type II cyclic AMP-dependent protein kinase may be a prerequisite in the short-term molecular action of LH leading to LH-specific phosphorylation of several soluble granulosa cell proteins of an as yet unidentified function.