HORMONAL-REGULATION OF 3',5'-ADENOSINE-MONOPHOSPHATE PHOSPHODIESTERASES IN CULTURED RAT GRANULOSA-CELLS
HORMONAL-REGULATION OF 3',5'-ADENOSINE-MONOPHOSPHATE PHOSPHODIESTERASES IN CULTURED RAT GRANULOSA-CELLS
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DOI：
10.1210/endo-114-6-2361
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发表时间：
1984-01-01
期刊：
影响因子：
4.8
通讯作者：
HSUEH, AJW
中科院分区：
文献类型：
--
作者：
CONTI, M;KASSON, BG;HSUEH, AJW
在体外模型中研究了促性腺激素对大鼠颗粒细胞磷酸二酯酶活性的影响。从垂体切除或完整的雌激素致敏的未成熟雌性大鼠中制备颗粒细胞，并在体外用FSH、人绒毛膜促性腺激素[hCG]或（Bu）2cAMP处理。在细胞匀浆中测定磷酸二酯酶活性。FSH治疗2天产生了显着增加磷酸二酯酶活性，而hCG是无效的。FSH刺激通过加入1-甲基-3-异丁基黄嘌呤而增强，而用cAMP类似物（Bu）2cAMP本身处理也显著刺激酶活性。FSH刺激cAMP而非cGMP水解，表明促性腺激素刺激cAMP特异性磷酸二酯酶。时间进程研究表明，磷酸二酯酶活性的增加是明显的孵育后1小时，并在48小时达到最大。FSH对磷酸二酯酶的刺激呈剂量依赖性，ED 50为30 ng/ml FSH，最大增加量为100-300 ng/ml。用放线菌酮（1或10 μ g/ml）处理完全阻断促性腺激素刺激，表明FSH作用需要持续的蛋白质合成。对照组和FSH处理组细胞可溶性提取物的DEAE-纤维素层析表明，在未受刺激的颗粒细胞中存在2种形式的磷酸二酯酶。第一种形式，在0.17 M乙酸钠洗脱水解cAMP和cGMP，并刺激钙2+和钙调素;第二种形式，在0.48 M乙酸钠洗脱，对钙2+或钙调素不敏感，主要水解cAMP。FSH处理显著刺激cAMP水解的钙调素依赖性的第一形式，以及由第二形式。双倒数分析表明，FSH刺激的酶对cAMP具有高亲和力。cGMP水解不受激素处理的影响。FSH在体外刺激大鼠颗粒细胞中cAMP而非cGMP磷酸二酯酶活性。这种刺激可能代表了终止FSH初级刺激和调节颗粒细胞对促性腺激素反应性的机制。
The effect of gonadotropins on phophodiesterase activity of rat granulosa cells was studied in an in vitro model. Granulosa cells were prepared from hypophysectomized or intact, estrogen-primed immature female rats and treated with FSH, human chorionic gonadotropin [hCG] or (Bu)2cAMP in vitro. Phosphodiesterase activity was determined in cell homogenates. FSH treatment for 2 days produced a marked increase in phosphodiesterase activity, while hCG was ineffective. FSH stimulation was potentiated by the addition of 1-methyl-3-isobutylxanthine, while treatment with the cAMP analog, (Bu)2cAMP by itself also markedly stimulated enzyme activity. FSH stimulated cAMP, but not cGMP, hydrolysis, suggesting that a phosphodiesterase specific for cAMP was stimulated by the gonadotropin. Time-course studies showed that an increase in phosphodiesterase activity was apparent after 1 h of incubation and was maximal at 48 h. FSH stimulation of phosphodiesterase was dose-dependent, with an ED50 of 30 ng/ml FSH and a maximal increase at 100-300 ng/ml. Treatment with cycloheximide (1 or 10 .mu.g/ml) completely blocked the gonadotropin stimulation, suggesting that on-going protein synthesis is required for the FSH action. DEAE-cellulose chromatography of soluble extracts of control and FSH-treated cells indicated that 2 forms of phosphodiesterase were present in unstimulated granulosa cells. The 1st form, eluting at 0.17 M Na-acetate hydrolyzed both cAMP and cGMP, and was stimulated by Ca2+ and calmodulin; the 2nd from, eluting at 0.48 M Na-acetate, was insensitive to Ca2+ or calmodulin, and hydrolyzed mainly cAMP. FSH treatment markedly stimulated cAMP hydrolysis by the calmodulin-dependent 1st form as well as that by the 2nd form. Double reciprocal analysis indicated that the FSH-stimulated enzymes are of high affinity for cAMP. The cGMP hydrolysis was not affected by the hormone treatment. FSH stimulates cAMP, but not cGMP, phosphodiesterase activity in rat granulosa cells in vitro. This stimulation might represent a mechanism for termination of the FSH primary stimulus and regulation of granulosa cell responsiveness to the gonadotropin.