Mechanisms of suppression of ovarian follicular development during lactation in the rat.
Mechanisms of suppression of ovarian follicular development during lactation in the rat.
复制标题
大鼠哺乳期间抑制卵泡发育的机制。
DOI：
10.1095/biolreprod27.5.1090
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发表时间：
1982
影响因子：
3.6
通讯作者：
Gilbert S. Greenwald
中科院分区：
文献类型：
--
作者：
Kazuyoshi Taya;Gilbert S. Greenwald
为了确定哺乳期大鼠卵泡发育受到抑制的机制，在体内和体外测定类固醇和肽类激素，并结合卵泡的组织学大小分布，比较了三组产后大鼠哺乳0，2或8只幼崽。从第4天至第12天（分娩日=哺乳期第0天），在哺乳8只幼仔的母鼠中，不存在直径大于401 μ m的卵泡，而在哺乳0或2只幼仔的母鼠中始终存在该尺寸的卵泡。哺乳8只幼崽的母鼠的非黄体卵巢组织（NLO）的雌二醇-17 β（E2）和睾酮（T）的体外产生率始终低于哺乳0只或2只幼崽的母鼠，这与组织学观察结果相关。与0或2只幼崽的母鼠相比，8只幼崽的大鼠血清E2和20 α-二氢孕酮（20 α-OHP）显著降低，而血清孕酮（P）显著升高。在母亲哺乳8幼崽，黄体（CL）的哺乳期，在产后排卵形成，在体外产生显着更大量的P，但显着较少的量E2相比，其他组。哺乳8只幼仔的母鼠血清促黄体生成素（LH）始终低于哺乳0或2只幼仔的母鼠。但三种产后大鼠血清促卵泡激素（FSH）无显著差异。在整个哺乳期，血清FSH值均在发情周期的间情期水平范围内。哺乳8只幼鼠的母鼠血清催乳素（PRL）水平显著高于哺乳2只幼鼠的母鼠。从第2天至第5天，向哺乳8只幼崽的哺乳期大鼠每日两次给予小剂量人绒毛膜促性腺激素（hCG）或绵羊LH，诱导能够排卵的卵泡成熟。这些结果表明，在哺乳期的前半期，强烈的哺乳刺激直接或间接地降低血清LH通过高水平的血清PRL和P，这反过来又抑制卵泡成熟。在哺乳的后半段，哺乳刺激减弱，Prl和P下降，血清LH恢复到基础周期值，这反映在卵泡成熟的开始。
To determine the mechanisms responsible for the suppression of follicular development in the lactating rat, in vivo and in vitro determinations of steroid and peptide hormones combined with the histological size-distribution of ovarian follicles were compared among three groups of post-parturient rats nursing 0, 2 or 8 pups. From Days 4 to 12 (day of parturition = Day 0 of lactation), in dams nursing 8 pups, follicles larger than 401 microns in diameter were absent, whereas follicles of this size were always present in mothers nursing 0 or 2 pups. The in vitro production rates of estradiol-17 beta (E2) and testosterone (T) by nonluteal ovarian tissues (NLO) were consistently lower in dams nursing 8 pups than in mothers nursing 0 or 2 young, correlating with the histological observations. Serum E2 and 20 alpha-dihydroprogesterone (20 alpha-OHP) in rats with 8 pups were significantly lower, whereas serum progesterone (P) was significantly increased compared to the values in dams nursing 0 or 2 pups. In mothers nursing 8 pups, the corpora lutea (CL) of lactation, formed at postpartum ovulation, produced in vitro significantly greater amounts of P but significantly lesser amount of E2 compared to the other groups. Serum luteinizing hormone (LH) was consistently lower in dams nursing 8 pups than in dams nursing 0 or 2 pups. There was, however, no significant difference in serum follicle-stimulating hormone (FSH) among the 3 types of postparturient rats. Throughout lactation serum values of FSH were within the range of diestrous levels during the estrous cycle. Serum levels of prolactin (Prl) in dams nursing 8 pups were strikingly higher compared to dams nursing 2 pups. The administration of small doses of human chorionic gonadotropin (hCG) or ovine LH twice daily from Days 2 to 5 to lactating rats nursing 8 pups induced the maturation of follicles capable of ovulating. These findings indicate that during the first half of lactation the strong suckling stimulus reduces serum LH directly or indirectly via high levels of serum Prl and P, which in turn inhibit follicular maturation. During the second half of lactation, the suckling stimulus wanes, Prl and P decline and serum LH recovers to basal cyclic values which are reflected in the initiation of follicular maturation.