Fleet I R, Davis A J, Goode J A, Hamon M, Collier R J, Heap R B
Babraham Institute, Cambridge, UK.
J Reprod Fertil. 1994 Mar;100(2):623-8. doi: 10.1530/jrf.0.1000623.
Prostaglandin F2 alpha (PGF2 alpha)-induced release of ovarian oxytocin was investigated to determine whether the effect in vivo was local. [3H]PGF2 alpha infused downstream into a single ovarian lymphatic was transferred into the adjacent ovarian vasculature (estimated transfer 1.1 and 1.7%, two experiments). When unlabelled PGF2 alpha was infused in a similar manner (76 pmol min-1), there was a prompt eightfold increase in ovarian oxytocin release from the adjacent ovary containing a corpus luteum, but no effect on the opposite corpus luteum, showing that the effect was local. Instillation of 2% lignocaine into the ovarian vascular pedicle did not affect PGF2 alpha-induced oxytocin release, supporting the idea that neural mechanisms are not involved. Repeated doses of PGF2 alpha given close-arterially produced a successive reduction in oxytocin release. This effect was prevented by a prior infusion of insulin-like growth factor-I (IGF-I), which itself gave a small, but significant, increase in oxytocin release. The results show that PGF2 alpha in ovarian lymphatics acts locally and directly to stimulate ovarian oxytocin secretion, that repeated exposure of the corpus luteum to pulses of PGF2 alpha can result in tachyphylaxis, and that this latter effect can be ameliorated by IGF-I infused in vivo.
研究了前列腺素F2α（PGF2α）诱导的卵巢催产素释放，以确定其体内作用是否为局部性的。将[3H]PGF2α注入单个卵巢淋巴管下游，会转移至相邻的卵巢血管系统（在两个实验中，估计转移率分别为1.1%和1.7%）。当以类似方式注入未标记的PGF2α（76 pmol·min-1）时，含有黄体的相邻卵巢的催产素释放迅速增加了八倍，但对另一侧黄体没有影响，表明该作用是局部性的。向卵巢血管蒂内注入2%利多卡因并不影响PGF2α诱导的催产素释放，支持了神经机制未参与的观点。经动脉给予重复剂量的PGF2α会使催产素释放相继减少。预先注入胰岛素样生长因子-I（IGF-I）可防止这种作用，而IGF-I本身会使催产素释放有小幅但显著的增加。结果表明，卵巢淋巴管中的PGF2α通过局部直接作用刺激卵巢催产素分泌，黄体反复暴露于PGF2α脉冲会导致快速耐受，而在体内注入IGF-I可改善后一种作用。
