Alexandris E, Milingos S, Kollios G, Seferiadis K, Lolis D, Messinis I E
State and University Department of Obstetrics and Gynaecology, Larissa, Greece.
Clin Endocrinol (Oxf). 1997 Dec;47(6):721-6. doi: 10.1046/j.1365-2265.1997.3461141.x.
Pituitary responsiveness to GnRH varies throughout the normal menstrual cycle. We have investigated whether there are differences in the ovarian mechanisms which regulate gonadotrophin secretion between the follicular and the luteal phase of the cycle.
Normally ovulating women were studied during the first week following hysterectomy plus bilateral ovariectomy performed either in the mid- to late follicular phase (follicle size 16 mm) or in the early to midluteal phase (5 days post LH peak). The response of LH to a single dose of 10 micrograms GnRH was investigated 2 hours before the operation and every 12 hours after the operation until postoperative day 4 and every 24 hours until day 8.
Fourteen normally cycling premenopausal women with normal FSH (< 10 IU/l). Seven women were ovariectomized in the follicular and 7 in the luteal phase.
Pituitary response to GnRH was calculated as the net increase in FSH (delta FSH) and LH (delta LH) at 30 minutes above the basal value.
Basal levels of FSH and LH before the operation were significantly lower in the luteal than the follicular phase (P < 0.05), while those of oestradiol (E2) were similar. Also, similar were delta LH and delta FSH values. Serum progesterone and immunoreactive inhibin (Ir-inhibin) concentrations before the operation were higher in the luteal than the follicular phase (P < 0.05). Following the operation, serum E2, progesterone and Ir-inhibin values declined dramatically, while basal FSH and LH as well as delta FSH values showed a gradual and significant increase. The percentage increase in FSH and LH values (mean +/- SEM) on day 8 after the operation was similar in the follicular (453 +/- 99% and 118 +/- 35% respectively) and the luteal phase (480 +/- 71% and 192 +/- 45% respectively). In contrast to delta FSH, delta LH values after a temporal increase 12 hours from the operation, remained stable in the follicular phase and declined significantly in the luteal phase up to day 4.
Basal gonadotrophin secretion during the normal menstrual cycle is predominantly under a negative ovarian effect. It is suggested that in contrast to FSH, the secretion of LH in response to GnRH is controlled by different ovarian mechanisms during the two phases of the menstrual cycle.
垂体对促性腺激素释放激素（GnRH）的反应在正常月经周期中会有所变化。我们研究了在月经周期的卵泡期和黄体期，调节促性腺激素分泌的卵巢机制是否存在差异。
对正常排卵的女性进行研究，这些女性在子宫切除加双侧卵巢切除术后的第一周接受观察，手术分别在卵泡期中期至晚期（卵泡大小16mm）或黄体期早期至中期（促黄体生成素（LH）峰值后5天）进行。在手术前2小时以及手术后每12小时直至术后第4天、每24小时直至第8天，研究LH对单剂量10微克GnRH的反应。
14名月经周期正常、促卵泡生成素（FSH）水平正常（<10IU/L）的绝经前女性。7名女性在卵泡期进行卵巢切除，7名在黄体期进行卵巢切除。
垂体对GnRH的反应通过计算30分钟时促卵泡生成素（FSH）和促黄体生成素（LH）相对于基础值的净增加量（△FSH和△LH）来评估。
手术前黄体期FSH和LH的基础水平显著低于卵泡期（P<0.05），而雌二醇（E2）的基础水平相似。同样，△LH和△FSH值也相似。手术前黄体期血清孕酮和免疫反应性抑制素（Ir-抑制素）浓度高于卵泡期（P<0.05）。手术后，血清E2、孕酮和Ir-抑制素值急剧下降，而基础FSH和LH以及△FSH值则逐渐显著升高。手术后第8天，卵泡期FSH和LH值的升高百分比（平均值±标准误）分别为453±99%和118±35%，黄体期分别为480±71%和192±45%。与△FSH不同，手术后12小时短暂升高后，卵泡期的△LH值保持稳定，而黄体期至第4天则显著下降。
正常月经周期中基础促性腺激素分泌主要受卵巢的负反馈作用影响。提示与FSH不同，月经周期两个阶段中GnRH刺激下LH的分泌受不同卵巢机制的控制。
