Cagnacci A, Melis G B, Paoletti A M, Soldani R, Fioretti P
Department of Obstetrics and Gynecology, University of Pisa, School of Medicine, Italy.
J Clin Endocrinol Metab. 1990 Feb;70(2):365-70. doi: 10.1210/jcem-70-2-365.
Estrogens exert both inhibitory and stimulatory effects on the secretion of GnRH and gonadotropins in women. The endogenous opioid peptides seem to mediate, at least in part, the inhibitory action exerted by estrogens on LH secretion. However, the mechanisms that mediate the stimulatory effect of estrogens on LH secretion are still unclear. The present study was performed to evaluate whether the endogenous opioid peptides could also participate in the stimulatory effect that estrogens exert on the gonadotropin response to GnRH. In postmenopausal women, a GnRH test was performed both under basal conditions and during the second month of treatment with transdermal 17 beta-estradiol (E2). In untreated postmenopausal women, two different doses of naloxone infusion failed to modify the LH and FSH responses to GnRH stimulation. During treatment with transdermal E2, the LH response to GnRH was significantly increased, while the FSH response was similar to that before treatment. Naloxone completely counteracted the enhanced LH response to GnRH observed during E2 treatment. On the other hand, naloxone did not significantly modify the FSH response to GnRH. The present results confirm that E2 exerts a sensitizing effect on the pituitary LH response to GnRH and suggest that the endogenous opioid system could be involved in this effect.
雌激素对女性促性腺激素释放激素（GnRH）和促性腺激素的分泌具有抑制和刺激作用。内源性阿片肽似乎至少部分介导了雌激素对促黄体生成素（LH）分泌的抑制作用。然而，介导雌激素对LH分泌刺激作用的机制仍不清楚。本研究旨在评估内源性阿片肽是否也参与雌激素对GnRH刺激的促性腺激素反应的刺激作用。在绝经后妇女中，在基础条件下以及在用经皮17β-雌二醇（E2）治疗的第二个月期间进行了GnRH试验。在未经治疗的绝经后妇女中，两种不同剂量的纳洛酮输注未能改变LH和FSH对GnRH刺激的反应。在用经皮E2治疗期间，LH对GnRH的反应显著增加，而FSH反应与治疗前相似。纳洛酮完全抵消了E2治疗期间观察到的LH对GnRH增强的反应。另一方面，纳洛酮并未显著改变FSH对GnRH的反应。目前的结果证实E2对垂体LH对GnRH的反应具有致敏作用，并表明内源性阿片系统可能参与了这一作用。
