Shander D, Goldman B
Endocrinology. 1978 Oct;103(4):1383-93. doi: 10.1210/endo-103-4-1383.
The significance of ovarian estradiol (E2) and progesterone secretion in the regulation of pituitary LH and FSH secretion and pituitary responses to LHRH was investigated in the hamster. Cycling females showed increased LH and FSH responses to LHRH on the morning of proestrus as compared to the responses observed on diestrus day 2. Pituitary responsiveness to LHRH declined on the evening of proestrus, after the preovulatory LH/FSH release. The secondary increase in serum FSH concentration on the morning of estrus was accompanied by a selective increase in the pituitary FHS response to exogenous LHRH. Hamsters ovariectomized (ovx) on diestrus day 2 exhibited daily afternoon LH surges but not FSH surges for at least 10 days after ovx. The magnitude of the LH surges in ovx hamsters was approximately 30-50% of that observed in proestrous females. The pituitary LH response to exogenous LHRH in ovx animals was about 25% as great as in proestrus hamsters. Serum FSH concentrations in ovx females increased by only 30% after LHRH injection, while similar treatment with LHRH resulted in 3- to 4-fold increments in serum FSH in proestrous hamsters. Implantation of E2 capsules in ovx hamsters resulted in increased gonadotropin responses to exogenous LHRH. Serum LH concentrations in the E2-implanted, LHRH-injected animals were as great as those observed after LHRH injection in proestrous females. Administration of LHRH, LH, or progesterone on the morning of proestrus failed to detectably alter the timing or magnitude of the proestrus afternoon FSH surge. The present results suggest that the increasing serum titers of estrogen on diestrus and early proestrus result in increased pituitary sensitivity to LHRH, and this increased sensitivity probably contributes to the magnitude of the preovulatory LH surge. The increases in LH and progesterone which occur during the afternoon do not seem to be responsible for triggering the proestrous FSH surge.
在仓鼠中研究了卵巢雌二醇（E2）和孕酮分泌在调节垂体促黄体生成素（LH）和促卵泡生成素（FSH）分泌以及垂体对促性腺激素释放激素（LHRH）反应方面的意义。与在动情间期第2天观察到的反应相比，处于发情周期的雌性仓鼠在发情前期早晨对LHRH的LH和FSH反应增强。在排卵前LH/FSH释放后，发情前期晚上垂体对LHRH的反应性下降。发情期早晨血清FSH浓度的二次升高伴随着垂体对外源性LHRH的FHS反应选择性增加。在动情间期第2天进行卵巢切除（ovx）的仓鼠在ovx后至少10天内每天下午出现LH峰，但未出现FSH峰。ovx仓鼠中LH峰的幅度约为发情前期雌性仓鼠中观察到的幅度的30 - 50%。ovx动物垂体对外源性LHRH的LH反应约为发情期仓鼠的25%。LHRH注射后，ovx雌性仓鼠的血清FSH浓度仅增加30%，而对发情前期仓鼠进行类似的LHRH处理则导致血清FSH增加3至4倍。在ovx仓鼠中植入E2胶囊导致对外源性LHRH的促性腺激素反应增强。在植入E2并注射LHRH的动物中，血清LH浓度与发情前期雌性仓鼠注射LHRH后观察到的浓度一样高。在发情前期早晨给予LHRH、LH或孕酮未能显著改变发情前期下午FSH峰的时间或幅度。目前的结果表明，动情间期和发情前期早期血清雌激素水平的升高导致垂体对LHRH的敏感性增加，这种增加的敏感性可能有助于排卵前LH峰的幅度。下午出现的LH和孕酮增加似乎不是触发发情前期FSH峰的原因。
