SOMATOMEDIN-C AS AN AMPLIFIER OF FOLLICLE-STIMULATING-HORMONE ACTION - ENHANCED ACCUMULATION OF ADENOSINE-3',5'-MONOPHOSPHATE
SOMATOMEDIN-C AS AN AMPLIFIER OF FOLLICLE-STIMULATING-HORMONE ACTION - ENHANCED ACCUMULATION OF ADENOSINE-3',5'-MONOPHOSPHATE
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DOI：
10.1210/endo-118-1-149
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发表时间：
1986-01-01
期刊：
影响因子：
4.8
通讯作者：
VANWYK, JJ
中科院分区：
文献类型：
--
作者：
ADASHI, EY;RESNICK, CE;VANWYK, JJ
最近发现生长调节素-C (Sm-C) 可以增强 FSH 介导的颗粒细胞孕激素生物合成能力、芳香酶活性和 LH 受体的获得，这种作用与其已建立的复制特性不同。为了进一步表征 Sm-C 与 FSH 协同相互作用的细胞机制，我们开始评估 cAMP 在这方面的中介作用。从未成熟垂体切除的己烯雌酚处理的大鼠中分离出的颗粒细胞在无血清条件下培养长达 3 天。高纯度 Sm-C (50 ng/ml) 处理后，cAMP 的基础细胞外积累保持不变。然而，同时使用增加浓度（0.3-50ng/ml）的Sm-C进行治疗，在FSH刺激的cAMP积累中产生剂量和时间依赖性增量，表观中位有效剂量（ED50；平均值.+-.SE）为5.1.+-。 0.6 ng/ml，最大反应比单独使用 FSH 诱导的反应高 8.8 倍，最短时间要求为 1-2 天。随着 FSH 浓度的增加，用恒定浓度 (50 ng/ml) 的 Sm-C 处理，对于 10、30 和 100 ng/ml FSH，cAMP 积累分别增加 1.7、5.8 和 4.3 倍。 Sm-C增强FSH刺激的cAMP积累的能力是明显的，并且事实上，通过ZK62711(Rolipram；3×10-6M)诱导的cAMP-磷酸二酯酶活性的阻断而增强。针对 Sm-C (sm 1.2) 的单克隆抗体的稀释度降低（1:64,000 至 1:1,000）可产生 Sm-C 与 FSH 协同相互作用的渐进和完全免疫中和，表明作用的特异性。总而言之，这些发现表明，Sm-C 在与其颗粒细胞受体结合亲和力 (0.6-2.0 nM) 相容的纳摩尔浓度下发挥作用，能够以时间和剂量依赖性方式放大 FSH 刺激的 cAMP 积累。这些观察结果表明，Sm-C 的协同作用至少部分地在接近 cAMP 生成的位点发挥。
Somatomedin-C (Sm-C) has recently been found to amplify the FSH-mediated acquisition of granulosa cell progestin biosynthetic capacity, aromatase activity, and LH receptors, an effect distinct from its established replicative property. To further characterize the cellular mechanism(s) underlying the synergistic interaction of Sm-C with FSH, we have set out to evaluate the intermediary role of cAMP in this regard. Isolated granulosa cells from immature hypophysectomized diethylstilbestrol-treated rats were cultured for up to 3 days under serum-free conditions. The basal extracellular accumulation of cAMP remained unchanged in response to treatment with highly purified Sm-C (50 ng/ml). However, concurrent treatment with increasing concentrations (0.3-50 ng/ml) of Sm-C, produced dose- and time-dependent increments in the FSH-stimulated accumulation of cAMP, with an apparent median effective dose (ED50; mean .+-. SE) of 5.1 .+-. 0.6 ng/ml, a maximal response 8.8-fold greater than that induced by FSH alone, and a minimal time requirement of 1-2 days. Given increasing concentrations of FSH, treatment with a constant concentration (50 ng/ml) of Sm-C resulted in 1.7-, 5.8-, and 4.3-fold increases in cAMP accumulation for 10, 30, and 100 ng/ml FSH, respectively. The ability of Sm-C to augment FSH-stimulated cAMP accumulation was evident and, in fact, enhanced by ZK62711 (Rolipram; 3 .times. 10-6 M)-induced blockade of cAMP--phosphodiesterase activity. Decreasing dilutions (1:64,000 to 1:1,000) of a monoclonal antibody raised against Sm-C (sm 1.2) produced progressive and complete immunoneutralization of the synergistic interaction of Sm-C with FSH, suggesting specificity of action. Taken together, these findings suggest that Sm-C, acting at nanomolar concentrations compatible with its granulosa cell receptor binding affinity (0.6-2.0 nM), is capable of amplifying FSH-stimulated cAMP accumulation in a time- and dose-dependent manner. These observations suggest that the synergistic action of Sm-C is exerted, at least in part, at a site(s) proximal to cAMP generation.