Dimitraki Marina, Koutlaki Nikoletta, Gioka Theodora, Messini Christina I, Dafopoulos Konstantinos, Anifandis George, Messinis Ioannis E
Department of Obstetrics and Gynaecology, School of Health Sciences, Faculty of Medicine, University of Thessaly, Larissa, Greece.
Department of Obstetrics and Gynaecology, Medical School, University of Thrace, Alexandroupolis, Greece.
Clin Endocrinol (Oxf). 2015 Sep;83(3):377-83. doi: 10.1111/cen.12735. Epub 2015 Mar 6.
It has been reported that the positive feedback mechanism of oestrogens and progesterone is preserved, although attenuated, in late postmenopausal years. Whether this is also true for the positive feedback effect of oestrogens alone has not been investigated.
Prospective intervention study.
Thirty healthy postmenopausal women.
The women were divided into three groups according to the years since menopause (group I: 2-8 years, group II: 9-17 years, group III: 18-25 years). They were studied during a period of 41 days. Two acute experiments (EP) of exogenous oestradiol, given via skin patches, were performed from days 1 to 7 (EP1) and from days 35 to 41 (EP2) to induce an LH surge. Between the two experiments (days 7-34), oestradiol was given at the dose of 100 μg every 3 days, while oral progesterone was added from day 21 to day 34 in order to simulate a luteal phase. Blood samples were taken every 6 h during EP1 and EP2 as well as on days 8, 13, 20, 21, 27 and 34. FSH, LH, oestradiol and progesterone were measured in all blood samples.
An LH surge occurred as a result of the oestradiol positive feedback mechanism in group I and in group II, in both EP1 and EP2. Peak LH values during the surge were significantly lower in group II than in group I in both experiments. None of the patients in group III displayed an LH surge.
These results demonstrate for the first time a gradual attenuation of the pituitary response to oestrogenic provocation over a certain period following the menopause, with complete abolition after 20 years. It is suggested that the reserves of pituitary gonadotrophs diminish with age.
据报道，绝经后期雌激素和孕激素的正反馈机制虽有所减弱但依然存在。单独雌激素的正反馈效应是否如此尚未得到研究。
前瞻性干预研究。
30名健康绝经后女性。
根据绝经年限将女性分为三组（第一组：2 - 8年，第二组：9 - 17年，第三组：18 - 25年）。她们接受为期41天的研究。在第1至7天（实验1）和第35至41天（实验2）通过皮肤贴片进行两次外源性雌二醇的急性实验（EP）以诱导促黄体生成素（LH）激增。在两次实验之间（第7 - 34天），每3天给予100μg雌二醇，同时从第21天至第34天添加口服孕激素以模拟黄体期。在实验1和实验2期间以及第8、13、20、21、27和34天每6小时采集血样。测量所有血样中的促卵泡生成素（FSH）、促黄体生成素（LH）、雌二醇和孕激素。
在实验1和实验2中，第一组和第二组因雌二醇正反馈机制出现LH激增。在两次实验中，第二组激增期间的LH峰值均显著低于第一组。第三组患者均未出现LH激增。
这些结果首次证明绝经后一段时间内垂体对雌激素刺激的反应逐渐减弱，20年后完全消失。提示垂体促性腺细胞储备随年龄减少。
