Cyclic gonadotropin release in the presence and absence of estrogenic feedback in ovariectomized golden hamsters.
Cyclic gonadotropin release in the presence and absence of estrogenic feedback in ovariectomized golden hamsters.
复制标题
去卵巢金仓鼠在存在和不存在雌激素反馈的情况下循环促性腺激素的释放。
作者：
M. Stetson;M. Watson;K. Matt
卵巢切除术后2周或3周，饲养在14小时光照/天（光照0600-2000 h）的成年仓鼠a）接受含有结晶雌二醇-1713的5 mm硅橡胶植入物，B）接受空植入物或c）不接受植入物。断头后1、3、5天，用放射免疫法测定血清促黄体生成素（LH）和促卵泡激素（FSH）。所有动物均在1300 - 1800 h之间显示LH释放峰值。在卵巢切除术后5周通过心脏穿刺取样的雌性动物中观察到类似的结果。FSI-I的释放变化更大;在每个组中均无法辨别出循环模式。暴露于雌二醇1天诱导的LH水平与发情前期下午自发LH释放期间观察到的水平相似。这些动物的FSH水平比发情前期水平高3倍。雌二醇与LH和FSH峰值水平的降低相关，FSH组的垂体LH和FSH水平显著升高，高于发情前期相似时期内采样的完整雌性动物中观察到的水平。在有空植入物或无植入物的去势动物中，垂体LH升高3-5倍，垂体FSH升高13-18倍，高于在完整的发情前期仓鼠中观察到的水平。暴露于雌二醇1天导致垂体LH显著增加，但FSH没有。垂体促性腺激素含量减少，长期暴露于雌二醇，但即使在5天后，腺体内容仍然显着大于在完整的发情前期仓鼠。这些结果表明，内源性起搏器的时间在生殖成熟的雌性仓鼠促性腺激素的释放和雌二醇的作用，以改变LH和FSH的合成和释放。到
Two or 3 weeks after ovariectomy, adult hamsters housed on 14 h of light/day (lights 0600-2000 h) a) received a 5 mm Silastic implant containing crystalline-estradiol-1713, b) received an empty implant or c) received no implant. Following decapitation 1, 3 or 5 days later, serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured by radioimmunoassay. All animals demonstrated a peak release of LH between 1300 and 1800 h. Similar results were observed in females sampled by cardiac puncture 5 weeks after ovariectomy. FSI-I release was more varied; a cyclic pattern was not discernable in every group. Exposure to estradiol for 1 day induced levels of LH similar to those seen during spontaneous LH release on the afternoon of proestrus. FSH in these animals was elevated 3 times over proestrous levels. estradiol was correlated with reduction of peak levels of LH and FSH and of FSH groups, pituitary levels of LH and FSH were significantly elevated over those observed in intact females sampled over a similar period on the day of proestrus. In castrates with empty implants or with no implants, pituitary LH was elevated 3-5 times and pituitary FSH 13-18 times over levels observed in intact proestrous hamsters. Exposure to estradiol for 1 day resulted in a significant increase in pituitary LH, but not FSH. Pituitary gonadotropin content diminished with prolonged exposure to estradiol, though even after 5 days, glandular content remained significantly greater than that in intact proestrous hamsters. These results suggest that an endogenous pacemaker times gonadotropin release in reproductively mature female hamsters and that estradiol acts to alter synthesis and release of LH and FSH. to