Lieberman M E, Barnea A, Bauminger S, Tsafriri A, Collins W P, Lindner H R
Endocrinology. 1975 Jun;96(6):1533-42. doi: 10.1210/endo-96-6-1533.
Graafian follicles explanted from proestrous rats before the preovulatory gonadotropin surge secreted predominantly 17beta-estradiol, and only small amounts of progestins and androgens, during 12 h of culture in hormone-free medium. Addition of ovine luteinizing hormone (NIH-LH-S18; 0.1-1.0 mug/ml) to the medium stimulated within 1-2 h the rate of accumulation of these steroids. However, accumulation of androstenedione and estradiol ceased after 4-6 h in the LH-treated cultures, whereas progesterone continued to accumulate and became the major secretory product at 6-12 h. Incubation of the follicles with LH for only 5 min resulted in significant stimulation of the accumulation of progesterone, androstenedione and estradiol during a subsequent 6-h culture period in hormone-free medium containing antibodies to LH; 30 min exposure to the hormone sufficed to elicit a maximal steroidogenic response and to induce ovum maturation in 95% of the follicles. Addition of actinomycin D (act D; 8 mug/ml) within the first hour after exposure of follicles to LH suppressed the LH-effect on progesterone but augmented the LH effect on estradiol accumulation; when addition of this inhibitor was delayed until 2 h, progesterone accumulation continued unabated for a further 10 h. By contrast, puromycin (80 mug/ml) inhibited progesterone accumulation when added to the medium at any time (1, 2 or 3 h) after the hormone. It is suggested that (i) a short-lived protein is essential for the stimulatory effect of LH on follicular steroidogenesis; (ii) the act D-sensitive product (mRNA?) required for the production of this protein is synthesized in adequate amount during the first 2 h of LH action, and is stable for at least 10 h; and (iii) LH may stimulate the production of an additional act D-sensitive regulatory protein that inhibits enzymes engaged in the cleavage of the 17-side-chain of progesterone, or cells equipped with these enzymes.
在排卵前促性腺激素激增之前从动情前期大鼠取出的格拉夫卵泡，在无激素培养基中培养12小时期间，主要分泌17β-雌二醇，仅分泌少量孕激素和雄激素。向培养基中添加羊促黄体生成素（NIH-LH-S18；0.1 - 1.0微克/毫升）在1 - 2小时内刺激了这些类固醇的积累速率。然而，在LH处理的培养物中，雄烯二酮和雌二醇的积累在4 - 6小时后停止，而孕酮继续积累并在6 - 12小时成为主要分泌产物。卵泡与LH仅孵育5分钟导致在随后6小时的无激素培养基培养期间，在含有LH抗体的培养基中，孕酮、雄烯二酮和雌二醇的积累受到显著刺激；暴露于该激素30分钟足以引发最大的类固醇生成反应，并使95%的卵泡诱导卵母细胞成熟。在卵泡暴露于LH后的第一小时内添加放线菌素D（act D；8微克/毫升）抑制了LH对孕酮的作用，但增强了LH对雌二醇积累的作用；当该抑制剂的添加延迟至2小时时，孕酮积累在接下来的10小时内持续未减。相比之下，嘌呤霉素（80微克/毫升）在激素处理后的任何时间（1、2或3小时）添加到培养基中时，均抑制孕酮积累。提示：（i）一种短命蛋白对于LH对卵泡类固醇生成的刺激作用至关重要；（ii）该蛋白产生所需的act D敏感产物（mRNA？）在LH作用的前2小时内合成量充足，且至少稳定10小时；（iii）LH可能刺激产生另一种act D敏感调节蛋白，该蛋白抑制参与孕酮17-侧链裂解的酶或配备这些酶的细胞。
