INSULIN-LIKE GROWTH FACTOR-I AND INSULIN POTENTIATE LUTEINIZING HORMONE-INDUCED ANDROGEN SYNTHESIS BY RAT OVARIAN THECAL-INTERSTITIAL CELLS
INSULIN-LIKE GROWTH FACTOR-I AND INSULIN POTENTIATE LUTEINIZING HORMONE-INDUCED ANDROGEN SYNTHESIS BY RAT OVARIAN THECAL-INTERSTITIAL CELLS
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DOI：
10.1210/endo-123-2-733
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发表时间：
1988-08-01
期刊：
影响因子：
4.8
通讯作者：
ROSENFIELD, RL
中科院分区：
文献类型：
--
作者：
CARA, JF;ROSENFIELD, RL
我们检验了胰岛素样生长因子I（IGF-I）和胰岛素在大鼠卵巢膜间质细胞雄激素产生中发挥作用的假设。将从未成熟垂体切除的Sprague-Dawley大鼠中获得的胶原酶/DNA酶分散的大鼠卵巢膜间质细胞以106个细胞/ml的浓度在无血清培养基中培养，其中存在浓度递增的LH IGF-I或胰岛素。每48小时更换培养基，并将培养物上清液中的雄酮浓度用作雄激素产生的指标。在没有添加激素的情况下（对照），雄酮水平始终低于0.1 ng/ml。增加LH浓度以剂量依赖性方式刺激雄酮合成。IGF-I，在LH的情况下，没有显着增加雄酮水平高于对照值。然而，当与10 ng/ml LH组合时，IGF-I以剂量相关的方式使雄酮合成增加到高于单独使用LH所观察到的水平：例如，在培养96小时时，使用LH和100 ng/ml（13 nM）IGF-I所观察到的峰值雄酮水平显著高于单独使用10 ng/ml LH所观察到的峰值水平（302 ± 0.01）。71对17 +-。7ng/ml; P < 0.0125）。类似地，虽然单独的胰岛素没有使雄甾酮合成增加到对照值以上，但胰岛素与10 ng/ml LH组合增加了雄甾酮浓度;峰值为240 ± 0.001。67.7在用100 ng/ml（18 nM）胰岛素培养96小时时观察到100 ng/ml（P < 0.025，与单独的LH相比）。IGF-I和胰岛素的组合并没有增加雄酮合成水平高于单独使用每种激素所观察到的水平。IGF-I与卵巢细胞单层培养物上的高亲和性结合位点结合，表观结合亲和性为1.3 × 10 - 6。10-9 M.胰岛素也以剂量依赖性方式与放射性标记的IGF-I竞争结合，但胰岛素的亲和力约低500倍;[125 I]IGF-I结合的半数最大抑制发生在胰岛素浓度约300 nM（或约1700 ng/ml）。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳的膜间质细胞单层的亲和标记与放射性标记的IGF-I的存在和不存在的未标记的激素显示的蛋白质与I型IGF受体的特征。还注意到相对分子质量约为45，000的蛋白质的亲和标记，可能代表由膜间质细胞单层合成的IGF载体蛋白。未标记的IGF-I和胰岛素抑制I型IGF受体的亲和标记，但所需的胰岛素剂量是IGF-I的几倍，与这些肽对I型IGF受体的相对亲和力保持一致。我们的结论是，IGF-I和胰岛素协同LH刺激雄激素的正常卵巢卵泡膜间质细胞的生产。这些发现表明IGF-I和胰岛素在卵巢功能障碍综合征的病理生理学中的作用，包括卵泡膜间质细胞增生和高雄激素血症。
We tested the hypothesis that insulin-like growth factor I (IGF-I) and insulin play a role in androgen production by rat ovarian thecal-interstitial cells. Collagenase/DNase-dispersed rat ovarian thecal-interstitial cells obtained from immature hypophysectomized Sprague-Dawley rats were cultured at a concentration of 106 cells/ml in serum-free medium in the presence of increasing concentrations of LH IGF-I, or insulin. The medium was replaced every 48 h, and the androsterone concentration in the cultures supernatants was used as an index of androgen production. In the absence of added hormones (control) androsterone levels were consistently less than 0.1 ng/ml. Increasing concentrations of LH stimulated androsterone synthesis in a dose-dependent manner. IGF-I, in the absence of LH, did not significantly increase androsterone levels above control values. However, when combined with 10 ng/ml LH, IGF-I increased androsterone synthesis above levels seen with LH alone in a dose-related fashion: for example, the peak androsterone levels seen with LH and 100 ng/ml (13 nM) IGF-I at 96 h of culture were significantly greater than the peak level seen with 10 ng/ml LH alone (302 .+-. 71 vs. 17 .+-. 7 ng/ml; P < 0.0125). Similarly, while insulin alone did not increase androsterone synthesis above control values, androsterone concentrations were increased by insulin in combination with 10 ng/ml LH; a peak value of 240 .+-. 67.7 ng/ml was observed at 96 h of culture with 100 ng/ml (18 nM) insulin (P < 0.025 vs. LH alone) Androsterone levels were slightly less with insulin than with IGF-I, but this difference was not significant. The combination of IGF-I and insulin did not increase levels of androsterone synthesis above those observed with each hormone alone. IGF-I bound to a high affinity binding site on ovarian cell monolayer cultures with an apparent binding affinity of 1.3 .times. 10-9 M. Insulin also competed for binding with radiolabeled IGF-I in a dose-dependent manner, but the affinity of insulin was approximately 500-fold less; half-maximal inhibition [125I]IGF-I binding occurred with an insulin concentration of approximately 300 nM (or .apprx. 1700 ng/ml). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of thecal-interstitial cell monolayers affinity labeled with radiolabeled IGF-I in the absence and presence of unlabeled hormone revealed proteins with characteristics of type I IGF receptors. Affinity labeling to a protein of a relative molecular mass of approximately 45,000 was also noted, probably representing IGF carrier proteins synthesized by thecal-interstitial cell monolayers. Unlabeled IGF-I and insulin inhibited the affinity labeling of the type I IGF receptor, but the doses of insulin required were several-fold greater than those of IGF-I, in keeping with the relative affinities of these peptides for the type I IGF receptor. We conclude that IGF-I an insulin synergize with LH to stimulate androgen production by normal ovarian thecal-interstitial cells. These finding suggests a role for IGF-I and insulin in the pathophysiology of ovarian dysfunction syndromes involving thecal-interstitial cell hyperplasia and hyperandrogenism.