Jungclas B, Luck M R
J Endocrinol. 1986 Apr;109(1):R1-4. doi: 10.1677/joe.0.109r001.
We have examined the ability of granulosa cells, from carefully selected preovulatory bovine follicles, to secrete oxytocin in vitro. Although cells from 83% of follicles underwent functional luteinization (greatly increased progesterone secretion) in serum-supplemented culture, only 69% had cells capable of oxytocin secretion. Secretion followed a similar time course in all cultures, with the peak appearing on day 3. Oxytocin, but not progesterone, output could be consistently increased by addition of pieces of theca interna tissue, or theca conditioned medium, to the cultures. The effect could be achieved by exposure to theca tissue at any time prior to peak output without altering the time course of secretion. Oxytocin could not be detected in follicular fluid from any of the selected follicles, nor in medium from theca cultured alone. We conclude that the potential for oxytocin secretion is a feature of follicular maturation which is lost during atresia and that the stimulus to secretion is associated with luteinization but not with progesterone output. Finally, the intermixing of follicular cells during corpus luteum formation may provide a mechanism for the enhancement of oxytocin secretion within a predetermined time frame.
我们研究了从精心挑选的排卵前牛卵泡中获取的颗粒细胞在体外分泌催产素的能力。尽管在添加血清的培养物中，83%的卵泡细胞发生了功能性黄体化（孕酮分泌大幅增加），但只有69%的卵泡细胞能够分泌催产素。在所有培养物中，分泌遵循相似的时间进程，峰值出现在第3天。通过向培养物中添加卵泡内膜组织块或卵泡内膜条件培养基，催产素而非孕酮的分泌量可持续增加。在分泌峰值出现前的任何时间接触卵泡内膜组织均可产生此效应，且不会改变分泌的时间进程。在所选择的任何卵泡的卵泡液中，以及单独培养的卵泡内膜的培养基中，均未检测到催产素。我们得出结论，催产素分泌潜能是卵泡成熟的一个特征，在闭锁过程中会丧失，且分泌刺激与黄体化相关，而非与孕酮分泌量相关。最后，黄体形成过程中卵泡细胞的混合可能为在预定时间内增强催产素分泌提供一种机制。
