Tan C H, Lam T J, Wong L Y, Pang M K
Department of Zoology, National University of Singapore, Kent Ridge.
Prostaglandins. 1987 Nov;34(5):697-715. doi: 10.1016/0090-6980(87)90293-0.
Prostaglandin synthesis in vitro and its inhibition by dibutyryl cyclic AMP and forskolin were examined in postpartum follicles of the guppy. The follicles were cultured for up to 72h under chemically-defined conditions, and the synthesis of prostaglandins was determined by radioimmunoassay. The results show unequivocally that the ovarian follicles devoid of embryos can synthesize PGE and PGF from both endogenous precursors as well as added arachidonic acid. That this could be inhibited by indomethacin is indicative of active synthesis rather than release of preformed prostaglandins. Dibutyryl cAMP and forskolin also inhibited prostaglandin synthesis in a dose-dependent manner, as did 3-isobutyl-l-methylxanthine. A similar effect was also evident in vitellogenic oocytes surrounded by follicle layers at the yolk-globule stage of development. While the physiological significance of this action of the cyclic nucleotide remains uncertain at this stage, it is hypothesized that it could explain the non-occurrence of ovulation in this viviparous fish soon after final oocyte maturation.
对孔雀鱼产后卵泡中的前列腺素体外合成及其被二丁酰环磷酸腺苷和福斯可林抑制的情况进行了研究。卵泡在化学成分明确的条件下培养长达72小时，前列腺素的合成通过放射免疫测定法确定。结果明确显示，不含胚胎的卵巢卵泡能够从内源性前体以及添加的花生四烯酸合成PGE和PGF。吲哚美辛能够抑制这种合成，这表明是活跃合成而非预先形成的前列腺素的释放。二丁酰环磷酸腺苷和福斯可林也以剂量依赖的方式抑制前列腺素合成，3-异丁基-1-甲基黄嘌呤也是如此。在发育的卵黄球阶段被卵泡层包围的卵黄生成卵母细胞中也有类似的作用。虽然在现阶段这种环核苷酸作用的生理意义仍不确定，但据推测，这可以解释这种胎生鱼类在最终卵母细胞成熟后不久不排卵的现象。
