Iida T, Makino T, Saito S, Hara T, Iizuka R
Department of Obstetrics and Gynecology, School of Medicine, Keio University, Tokyo, Japan.
Endocrinol Jpn. 1990 Feb;37(1):87-94. doi: 10.1507/endocrj1954.37.87.
To investigate the postreceptor mechanism, especially the role of protein kinase C (C-kinase), in luteinizing hormone (LH) release from anterior pituitary cells, dispersed rat anterior pituitary cells were stimulated with luteinizing hormone-releasing hormone (LH-RH), [D-Ser(tBu)]6 des-Gly-NH2(10) ethylamide (Buserelin), 12-0-tetradecanoyl phorbol-13-acetate (TPA) and trifluoperazine (TFP) and the LH released into the medium was determined by radioimmunoassay. LH released by combined stimulation with TPA and either LH-RH or Buserelin was significantly less than that released by LH-RH or Buserelin alone (LH-RH: p less than 0.05; Buserelin: p less than 0.01). It is thought that this paradoxical phenomenon occurred due to desensitization accompanied by down-regulation of LH-RH receptors induced by TPA. This hypothesis was supported by the finding indicating that the binding capacity of LH-RH receptors decreased in a time-course manner during incubation with TPA. The amount of LH released by combined stimulation with TPA and TFP was significantly greater than with TPA alone (P less than 0.01). This suggests that TFP has dual actions, i.e., facilitating and inhibiting LH release.
为研究促黄体生成素（LH）从前体垂体细胞释放的受体后机制，尤其是蛋白激酶C（C激酶）的作用，用促黄体生成素释放激素（LH-RH）、[D-丝氨酸（叔丁基）]6去甘氨酰胺（10）乙酰胺（布舍瑞林）、12-O-十四酰佛波醇-13-乙酸酯（TPA）和三氟拉嗪（TFP）刺激分散的大鼠前体垂体细胞，并通过放射免疫测定法测定释放到培养基中的LH。TPA与LH-RH或布舍瑞林联合刺激释放的LH显著少于单独使用LH-RH或布舍瑞林释放的LH（LH-RH：p＜0.05；布舍瑞林：p＜0.01）。认为这种矛盾现象是由于TPA诱导的LH-RH受体下调伴随脱敏而发生的。这一假设得到了以下发现的支持，即与TPA孵育期间，LH-RH受体的结合能力呈时间依赖性下降。TPA与TFP联合刺激释放的LH量显著大于单独使用TPA时（P＜0.01）。这表明TFP具有双重作用，即促进和抑制LH释放。
