Uilenbroek J T, van der Schoot P, den Besten D, Lankhorst R R
Biol Reprod. 1982 Dec;27(5):1119-25. doi: 10.1095/biolreprod27.5.1119.
To examine whether high serum prolactin levels inhibit follicular maturation, prolactin was injected during diestrus of intact female rats or endogenous prolactin levels were raised by applying a suckling stimulus. Injections of rat prolactin (100 micrograms per injection) given 2 and 1 days before proestrus resulted in a lower estradiol production by proestrous follicles during a 4-h incubation period than follicles isolated from control rats. In 4 out of 7 animals this occurred without a change in serum progesterone and luteinizing hormone (LH) concentrations. In the 3 remaining animals corpus luteum function was activated. In these animals serum LH concentrations were decreased and follicular estradiol production was further suppressed. To study follicular development in the presence of suckling-induced hyperprolactinemia, the following experiment was performed. Removal of a 5-pup litter at Day 13 (0900 h) of lactation (Day 1 = day of parturition) resulted in ovulation at Day 16. Replacement of a new litter 24 h after litter removal did not interfere with ovulation on Day 16. This procedure allowed the study of follicular development between Days 14 and 15 in the presence of raised serum prolactin levels. It appeared that this treatment did not affect follicular growth, but in vitro estradiol production by preovulatory follicles isolated at Day 15 was lower than in follicles isolated from nonlactating animals. In 3 out of 13 animals corpus luteum function was reactivated. In these animals LH levels and follicular estradiol production were significantly suppressed. Treatment with bromocriptine (1 mg per injection) on Days 13 and 14, in addition to litter replacement, restored the high estradiol production at Day 15 without affecting serum LH concentrations. The results of this study demonstrate that in the presence of high prolactin levels, follicular estradiol production is low. The inverse relation between prolactin and follicular estradiol production in the presence of unchanged serum LH levels suggests that prolactin can have a direct action on estrogen biosynthesis of follicle cells.
为了研究高血清催乳素水平是否会抑制卵泡成熟，在完整雌性大鼠的动情间期注射催乳素，或通过给予哺乳刺激来提高内源性催乳素水平。在发情前期前2天和1天注射大鼠催乳素（每次注射100微克），与从对照大鼠分离出的卵泡相比，发情前期卵泡在4小时孵育期内产生的雌二醇减少。7只动物中有4只出现这种情况，同时血清孕酮和促黄体生成素（LH）浓度无变化。其余3只动物的黄体功能被激活。在这些动物中，血清LH浓度降低，卵泡雌二醇生成进一步受到抑制。为了研究在哺乳诱导的高催乳素血症情况下卵泡的发育，进行了以下实验。在哺乳期第13天（09:00）取出一窝5只幼崽（第1天 = 分娩日），导致在第16天排卵。在取出幼崽24小时后更换一窝新的幼崽，并不影响第16天的排卵。这个过程使得能够在血清催乳素水平升高的情况下研究第14天至15天期间卵泡的发育。结果显示，这种处理不影响卵泡生长，但在第15天分离出的排卵前卵泡的体外雌二醇生成低于从非哺乳动物分离出的卵泡。13只动物中有3只的黄体功能被重新激活。在这些动物中，LH水平和卵泡雌二醇生成受到显著抑制。在第13天和14天除了更换幼崽外，用溴隐亭（每次注射1毫克）进行治疗，恢复了第15天的高雌二醇生成，且不影响血清LH浓度。本研究结果表明，在高催乳素水平存在的情况下，卵泡雌二醇生成较低。在血清LH水平不变的情况下，催乳素与卵泡雌二醇生成之间的负相关关系表明，催乳素可能对卵泡细胞的雌激素生物合成具有直接作用。
