Batra S K, Miller W L
Endocrinology. 1985 Oct;117(4):1436-40. doi: 10.1210/endo-117-4-1436.
Progesterone (P4) regulation of LH secretion in sheep was studied in vitro using dispersed pituitary cell cultures. Neither cell content nor basal secretion of LH were normally altered by P4, but maximal stimulation of LH secretion by LHRH was suppressed up to 70% with 10(-7) M P4, without changing the ED50 of LHRH. The inhibitory effect of P4 appeared within 6 h and became maximal by 24 h but was partially reversed during continued treatment with P4. The inhibitory effect was completely reversed by 24 h after P4 withdrawal. The ED50 of P4 was 10(-9) M. P4 also decreased the sensitizing effect of 17 beta-estradiol (E2) on LHRH-induced LH secretion in ovine pituitary culture. It partially inhibited the E2-induced increase in maximal response to LHRH and decreased the ability of E2 to lower the ED50 of LHRH. Our results clearly show that P4 can act directly on the ovine pituitary to inhibit both normal and E2-sensitized LH responsiveness to LHRH.
采用分散垂体细胞培养的体外实验方法，研究了孕酮（P4）对绵羊促黄体生成素（LH）分泌的调节作用。P4对LH的细胞含量和基础分泌通常无影响，但在10⁻⁷ M P4作用下，LHRH对LH分泌的最大刺激作用被抑制高达70%，而LHRH的半数有效剂量（ED50）未改变。P4的抑制作用在6小时内出现，24小时达到最大，但在持续使用P4的过程中部分逆转。停用P4后24小时，抑制作用完全逆转。P4的ED50为10⁻⁹ M。P4还降低了17β - 雌二醇（E2）对绵羊垂体培养中LHRH诱导的LH分泌的致敏作用。它部分抑制了E2诱导的对LHRH最大反应的增加，并降低了E2降低LHRH的ED50的能力。我们的结果清楚地表明，P4可直接作用于绵羊垂体，抑制LH对LHRH的正常反应性以及E2致敏的反应性。
