Kawagoe S, Hiroi M
Department of Obstetrics and Gynecology, Yamagata University School of Medicine, Japan.
Gynecol Obstet Invest. 1989;27(4):197-200. doi: 10.1159/000293655.
To assess the role of prolactin (PRL) in the puberty onset and the ovarian aromatase activity, hyper- and hypoprolactinemic conditions were induced by treating chronically prepubertal female rats with PRL and bromocriptine, respectively. Injection of rat PRL (5 micrograms, twice daily) from day 20 onward advanced the day of vaginal opening. By contrast, the suppression of PRL release by bromocriptine, which was provided in the drinking water at a concentration of 40 micrograms/ml, caused a significant delay in the age of occurrence of vaginal opening. This bromocriptine-induced delayed puberty was prevented by the concomitant administration of exogenous PRL, suggesting that the effect of bromocriptine is exerted through its suppressive effect on the endogenous PRL release. The in vitro release of estradiol by the ovaries from 30-day-old rats treated with PRL was found to be higher than that from the control animals, when the ovaries were perifused for 6 h with an excess of androstenedione. On the other hand, the ovaries perifused in the presence of androgen produced less estradiol in the bromocriptine-treated rats than in their controls. It appears, therefore, that PRL is more likely related to the aromatase activity in the maturing ovary. These results suggest that PRL may be one of the factors that regulate the timing of puberty onset by influencing the aromatase activity in the ovary.
为评估催乳素（PRL）在青春期启动及卵巢芳香化酶活性中的作用，分别用PRL和溴隐亭长期处理青春期前雌性大鼠，诱导产生高催乳素血症和低催乳素血症状态。从第20天起每天注射两次大鼠PRL（5微克）可使阴道开口日提前。相比之下，以40微克/毫升的浓度加入饮用水中的溴隐亭抑制PRL释放，导致阴道开口出现的年龄显著延迟。同时给予外源性PRL可防止溴隐亭诱导的青春期延迟，这表明溴隐亭的作用是通过其对内源性PRL释放的抑制作用来实现的。当用过量雄烯二酮对卵巢进行体外灌流6小时时，发现用PRL处理的30日龄大鼠卵巢释放雌二醇的量高于对照动物。另一方面，在雄激素存在下进行体外灌流时，溴隐亭处理的大鼠卵巢产生的雌二醇比对照大鼠少。因此，PRL似乎更可能与成熟卵巢中的芳香化酶活性有关。这些结果表明，PRL可能是通过影响卵巢中的芳香化酶活性来调节青春期启动时间的因素之一。
