Hedin L, Ekholm C, Hillensjö T
Biol Reprod. 1983 Nov;29(4):895-904. doi: 10.1095/biolreprod29.4.895.
The secretion of steroids and the release of cAMP in response to repeated luteinizing hormone (LH) stimulation were examined during superfusion of isolated preovulatory rat follicles. A high dose of ovine LH (1 microgram/ml for 20 min) caused a prolonged increase in the secretion of progesterone (P) and 20 alpha-dihydroprogesterone (20 alpha-OHP) and a transient increase in the secretion of testosterone (T) and estradiol-17 beta (E2), and was accompanied by a peak of cAMP release. A single pulse of LH at a low dose level (10 mg/ml for 20 min) gave a limited increase in T secretion, but no clear change in P, 20 alpha-OHP and E2 secretion or cAMP release. When the follicles were challenged with a second pulse of LH (at 1 microgram/ml), the response varied according to the dose of LH delivered in the preceding pulse. Following exposure to the high dose of LH, the follicles were partially refractory to the second LH challenge in terms of cAMP and P and the secretion of T and E2 remained low. The low dose of LH, however, had a conditioning effect on the follicles since the response to the second LH challenge was amplified in terms of P, 20 alpha-OHP and cAMP. In this case a secondary increase in T and E2 secretion was found. The differential response to varying doses of LH are likely to reflect the physiological control of steroidogenesis during final follicular maturation.
在对分离的排卵前大鼠卵泡进行灌流期间，研究了类固醇的分泌以及对反复促黄体生成素（LH）刺激的环磷酸腺苷（cAMP）释放情况。高剂量的羊LH（1微克/毫升，持续20分钟）导致孕酮（P）和20α-二氢孕酮（20α-OHP）分泌持续增加，睾酮（T）和雌二醇-17β（E2）分泌短暂增加，并伴有cAMP释放峰值。低剂量水平的单次LH脉冲（10微克/毫升，持续20分钟）使T分泌有有限增加，但P、20α-OHP和E2分泌及cAMP释放无明显变化。当卵泡接受第二次LH脉冲（1微克/毫升）刺激时，反应根据前一次脉冲中LH的剂量而有所不同。在暴露于高剂量LH后，卵泡在cAMP和P方面对第二次LH刺激部分不应期，T和E2分泌仍保持在低水平。然而，低剂量LH对卵泡有预处理作用，因为对第二次LH刺激的反应在P、20α-OHP和cAMP方面被放大。在这种情况下，发现T和E2分泌有二次增加。对不同剂量LH的差异反应可能反映了卵泡最终成熟过程中类固醇生成的生理控制。
