Iida T, Makino T, Seki T, Iizuka R
Department of Obstetrics and Gynecology, School of Medicine, Keio University, Tokyo, Japan.
Endocrinol Jpn. 1989 Oct;36(5):739-46. doi: 10.1507/endocrj1954.36.739.
To investigate the mechanisms of the synthesis and the release of gonadotropin, rat anterior pituitary cells were stimulated in vitro with luteinizing hormone releasing hormone (LH-RH), [D-Ser(tBu)]6 des-Gly-NH2(10) ethylamide (Buserelin) and 12-0-tetradecanoyl phorbol-13-acetate (TPA), and then the LH and LH-beta subunit released into the medium were determined by radioimmunoassay. Buserelin showed its biological activity at a much lower concentration than LH-RH, but both of them caused the release of LH and LH-beta subunit in a dose-dependent manner. Furthermore, intracellular LH synthesis from LH-beta subunit by stimulation with LH-RH or Buserelin was also found. After inducing various degrees of desensitization by stimulation with LH-RH or Buserelin in a dose-dependent manner (the first stimulation), pituitary cells were stimulated with a fixed dose of TPA (the second stimulation) and the released LH was assayed. LH was released almost constantly by the second stimulation, regardless of the dose used for the first stimulation. These results suggest that the C-kinase pathway was unaffected by the desensitization induced with LH-RH or Buserelin.
为了研究促性腺激素合成与释放的机制，用促黄体生成激素释放激素（LH-RH）、[D-丝氨酸（叔丁基）]6 去甘氨酰胺（10）乙酰胺（布舍瑞林）和 12-0-十四酰佛波醇-13-乙酸酯（TPA）对大鼠垂体前叶细胞进行体外刺激，然后通过放射免疫测定法测定释放到培养基中的促黄体生成素（LH）和 LH-β亚基。布舍瑞林在比 LH-RH 低得多的浓度下就显示出其生物活性，但两者均以剂量依赖方式导致 LH 和 LH-β亚基的释放。此外，还发现通过 LH-RH 或布舍瑞林刺激可从 LH-β亚基合成细胞内 LH。在用 LH-RH 或布舍瑞林以剂量依赖方式进行刺激诱导不同程度的脱敏（第一次刺激）后，用固定剂量的 TPA 刺激垂体细胞（第二次刺激）并测定释放的 LH。无论第一次刺激所用的剂量如何，第二次刺激几乎都持续释放 LH。这些结果表明，C-激酶途径不受 LH-RH 或布舍瑞林诱导的脱敏影响。
