内皮素—1对大鼠排卵前卵泡颗粒细胞产生孕酮的影响

本文用离体细胞体外孵育法研究了内皮素－１（ＥＴ）对大鼠排卵前卵泡颗粒细胞孕酮生成的影响及其作用机理。结果发现，ＥＴ能显著抑制ｈＣＧ刺激下的孕酮产生，抑制作用在浓度为１０－８ｍｏｌ／Ｌ时，即有显著意义（Ｐ＜０．０５，ｎ＝６），至１０－７ｍｏｌ／Ｌ时则有非常显著的意义（Ｐ＜０．０１，ｎ＝６）；不同浓度ＥＴ（１０－７—１０－７ｍｏｌ／Ｌ），对颗粒细胞基础孕酮的产生无明显影响。进一步研究表明，ＥＴ对ｈＣＧ刺激下孕酮生成的抑制作用，在用免抗人内皮素抗血清（ＥＴ－Ａ）１：１０００及ｃＡＭＰ后能明显被逆转。实验中还观察到，ＥＴ使颗粒细胞ＬＨ／ｈＣＧ受体数下降，亲和力降低。本文结果提示，ＥＴ可能为卵巢内的一种局部调节肽，通过作用于ＥＴ受体，干扰ＬＨ／ｈＣＧ受体功能和ｃＡＭＰ生成而抑制颗粒细胞孕酮的产生。

EFFECTS OF ENDOTHELIN 1 ON THE PROGESTERONE PRODUCTION OF RAT PREOVULATORY OVARIAN GRANULOSA CELLS

The effect of endothelin-1 (ET) on progesterone production of isolated rat granulosa cells and its mechanism were investigated. ET could inhibit the hCG-stimulated progesterone production significantly at the concentration of 10(-8) mol/L (P < 0.05, n = 6) and highly significantly at the concentration of 10(-7) mol/L (P < 0.05, n = 6), but ET did not inhibit the basal progesterone production at various concentrations (10(-10)-10(-7) mol/L). Further experiments showed that the inhibitory effect of ET on the hCG-stimulated progesterone production could be reversed by rabbit antiserum to ET (ET-A, 1:1000) or cAMP (10(5) mol/L). ET could decrease the binding sites and the affinity constant (ka) of LH/hCG receptor on granulosa cells. All these findings suggest that ET may be an intraovarian regulatory factor which may inhibit progesterone production stimulated by hCG from rat granulosa cells through inerfering LH/hCG receptor function and cAMP formation.