DEVELOPMENT OF THE STEROIDOGENIC CAPACITY OF MEDAKA (ORYZIAS-LATIPES) OVARIAN FOLLICLES DURING VITELLOGENESIS AND OOCYTE MATURATION
DEVELOPMENT OF THE STEROIDOGENIC CAPACITY OF MEDAKA (ORYZIAS-LATIPES) OVARIAN FOLLICLES DURING VITELLOGENESIS AND OOCYTE MATURATION
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DOI：
10.1016/0016-6480(87)90242-5
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发表时间：
1987-06-01
影响因子：
2.7
通讯作者：
NAGAHAMA, Y
中科院分区：
文献类型：
--
作者：
SAKAI, N;IWAMATSU, T;NAGAHAMA, Y
采用18小时孵育法研究了青鳉卵黄发生和卵母细胞成熟过程中12个不同阶段卵泡类固醇合成能力的发育变化。使青鳉适应26 ℃的条件。在14小时光照和10小时黑暗的照明制度下。在这些条件下，雌性通常在光照开始后1小时内产卵。卵黄发生和卵母细胞成熟的过程发生在72小时内，生殖囊泡（GVBD）的破裂和排卵分别在6小时和1小时完成，在预期的产卵时间之前。产卵前32和16小时之间的卵黄发生卵泡产生大量的雌二醇-17 β。自发地和响应于部分纯化的鲑鱼促性腺激素（SGA）或孕马血清促性腺激素（PMSG）。然而，在产卵前12和4小时之间的卵黄发生后卵泡显示出很少的雌二醇-17 β的证据。生产相比之下，17 α，20. β-二羟基-4-异戊烯-3-酮（17 α，20. β- diOHprog）在卵黄发生期间的卵泡中保持非常低的水平，而在卵母细胞成熟期间收集的卵泡中升高; 17 α的培养基浓度之间存在密切关系，20. β- diOH-prog和卵母细胞中GVBD的百分比。17. α，20. β- DiOHprog生产响应PMSG是非常低的卵泡在早期和中期卵黄发生和增加在产卵前28小时收集的时间，正好与第一次收购的能力的卵泡进行成熟，响应促性腺激素。这些结果清楚地表明，从主要分泌雌二醇-17 β的明显转变。17 α的分泌，20. β- diOHprog在卵母细胞即将成熟之前出现在青鳉卵泡中。考虑到17 α的效力，20. β- diOHprog用于体外诱导卵母细胞成熟，这些结果进一步表明17 α，20. β- diOHprog是青鳉中卵母细胞成熟的天然类固醇介质。
Developmental changes in the steroidogenic capacity of medaka, Oryzias latipes, ovarian follicles at 12 different stages during vitellogenesis and oocyte maturation were examined using 18-hr incubations. Medaka were acclimated to conditions of 26.degree. on a lighting regime of 14 hr light and 10 hr dark. Under these conditions, females usually spawn daily within 1 hr of the onset of light. The process of vitellogenesis and oocyte maturation occurs within 72 hr, the breakdown of the germinal vesicle (GVBD) and ovulation being completed at 6 and 1 hr, respectively, before the expected time of spawning. Vitellogenic follicles between 32 and 16 hr before spawning produced large amounts of estradiol-17.beta. spontaneously and in response to partially purified chum salmon gonadotropin (SGA) or pregnant mare''s serum gonadotropin (PMSG). However, postvitellogenic follicles between 12 and 4 hr before spawning showed very little evidence of estradiol-17.beta. production. By contrast, basal concentrations of 17.alpha.,20.beta.-dihydroxy-4-pregnen-3-one (17.alpha.,20.beta.-diOHprog) remained very low in follicles during vitellogenesis and were elevated in those collected during oocyte maturation; there was a close relationship between the medium concentration of 17.alpha.,20.beta.-diOH-prog and the percentage GVBD in the oocytes. 17.alpha.,20.beta.-DiOHprog production in response to PMSG was very low in follicles during early and mid-vitellogenesis and increased in those collected at 28 hr before spawning, a time which coincided with the first acquisition of the ability of the follicles to undergo maturation in response to gonadotropin. These results clearly demonstrate that a distinct shift from the secretion of predominantly estradiol-17.beta. to the secretion of 17.alpha.,20.beta.-diOHprog occurs in the medaka ovarian follicle immediately prior to oocyte maturation. Considering the potency of 17.alpha.,20.beta.-diOHprog for the induction of oocyte maturation in vitro, these results further suggest that 17.alpha.,20.beta.-diOHprog is a naturally occurring steroidal mediator of oocyte maturation in the medaka.