Giguère V, Meunier H, Veilleux R, Labrie F
Endocrinology. 1982 Sep;111(3):857-62. doi: 10.1210/endo-111-3-857.
When present alone for 4 or 8 days, 5 alpha-dihydrotestosterone (DHT) or the pure progestin R5020 (17,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione) inhibits spontaneous PRL release by 33--50% in rat anterior pituitary cells in primary culture. This inhibitory effect of DHT and R5020 can only be partially reversed by 17 beta-estradiol (E alpha). DHT and R5020 inhibit spontaneous PRL release in E2-primed cells at ED50 values of 0.5 and 3 nM, respectively. While E2 diminishes by 30--60% the maximal inhibitory effect of dopamine on PRL release and increases by 10-fold the ED50 value of dopamine action, DHT and R5020 can prevent by 30--60% the action of E2 and thus increase the potency of dopamine to inhibit PRL release. The inhibitory action of DHT and R5020 as well as the stimulatory action of E2 on spontaneous PRL release are similarly expressed on TRH- and 3-isobutyl-1-methylxanthine-induced PRL release, thus suggesting that at least part of the highly effective modulatory effects of sex steroids are exerted at a step after cAMP formation.
单独存在4天或8天时，5α-双氢睾酮（DHT）或纯孕激素R5020（17,21-二甲基-19-去甲-4,9-孕二烯-3,20-二酮）可使原代培养的大鼠垂体前叶细胞中催乳素（PRL）的自发释放抑制33%-50%。DHT和R5020的这种抑制作用仅能被17β-雌二醇（E2）部分逆转。DHT和R5020分别在0.5 nM和3 nM的半数有效剂量（ED50）时抑制E2预处理细胞中PRL的自发释放。虽然E2可使多巴胺对PRL释放的最大抑制作用降低30%-60%，并使多巴胺作用的ED50值增加10倍，但DHT和R5020可阻止E2作用的30%-60%，从而增加多巴胺抑制PRL释放的效力。DHT和R5020的抑制作用以及E2对PRL自发释放的刺激作用在促甲状腺激素释放激素（TRH）和3-异丁基-1-甲基黄嘌呤诱导的PRL释放中同样表现出来，这表明性类固醇的至少部分高效调节作用是在环磷酸腺苷（cAMP）形成后的一个步骤发挥的。
