Yoshimura Y, Jinno M, Oda T, Shiokawa S, Yoshinaga A, Hanyu I, Akiba M, Nakamura Y
Department of Obstetrics and Gynecology, Kyorin University School of Medicine, Tokyo, Japan.
Biol Reprod. 1994 Jun;50(6):1223-30. doi: 10.1095/biolreprod50.6.1223.
The present study was undertaken to investigate the effects of prolactin (PRL) on gonadotropin-induced ovulation and the biosynthesis of prostaglandin (PG), leukotriene (LT), and plasmin in in vitro perfused rabbit ovaries. The addition of PRL to the perfusate inhibited hCG-induced ovulation in vitro in a dose-dependent manner. Although exposure to hCG significantly increased PGF2 alpha, PGE2, and LTB4 production by perfused rabbit ovaries, PRL did not affect the secretion rates of PGs and LTB4 stimulated by hCG administration. The ovarian plasmin generation was determined by measuring the amount of plasmin bound to its major inhibitor, alpha 2-plasmin inhibitor (alpha 2PI-Plm). Exposure to hCG enhanced biphasically the ovarian secretion rate of alpha 2 PI-Plm, while PRL at a dose of 10(3) ng/ml significantly inhibited the hCG-stimulated generation of alpha 2 PI-Plm in ovaries throughout the entire perfusion period. A significant correlation was observed between ovulatory efficiency and ovarian plasmin generation in the PRL-treated ovaries. Additionally, PRL inhibited intrafollicular concentrations of alpha 2 PI-Plm in hCG-treated ovaries in a dose-dependent manner. These observations substantiate an essential role for a plasma-generating system in the cascade of events leading to ovulation. In conclusion, PRL may act directly on the ovary and block ovulation, at least in part, via the inhibition of ovarian plasmin generation.
本研究旨在探讨催乳素（PRL）对促性腺激素诱导的排卵以及体外灌注兔卵巢中前列腺素（PG）、白三烯（LT）和纤溶酶生物合成的影响。向灌注液中添加PRL可在体外以剂量依赖的方式抑制hCG诱导的排卵。尽管暴露于hCG可显著增加灌注兔卵巢中PGF2α、PGE2和LTB4的产生，但PRL并不影响hCG给药刺激的PG和LTB4的分泌率。通过测量与主要抑制剂α2-纤溶酶抑制剂（α2PI-Plm）结合的纤溶酶量来测定卵巢纤溶酶的生成。暴露于hCG可双相增强卵巢α2PI-Plm的分泌率，而剂量为10³ ng/ml的PRL在整个灌注期间均显著抑制hCG刺激的卵巢中α2PI-Plm的生成。在PRL处理的卵巢中，排卵效率与卵巢纤溶酶生成之间存在显著相关性。此外，PRL以剂量依赖的方式抑制hCG处理的卵巢中卵泡内α2PI-Plm的浓度。这些观察结果证实了纤溶酶生成系统在导致排卵的一系列事件中的重要作用。总之，PRL可能直接作用于卵巢，并至少部分通过抑制卵巢纤溶酶生成来阻断排卵。
