胰高血糖素和甲状腺激素-胰高血糖素对离体大鼠肝细胞类固醇代谢的影响。
The effects of glucagon and TH-glucagon on steroid metabolism in isolated rat hepatocytes.
作者信息
Hussin A H, Allan C J, Hruby V J, Skett P
机构信息
Department of Pharmacology, The University, Glasgow, Scotland, U.K.
出版信息
Mol Cell Endocrinol. 1988 Feb;55(2-3):203-7. doi: 10.1016/0303-7207(88)90135-9.
Glucagon decreases the activity of steroid-metabolising enzymes in isolated rat liver cells at physiological concentrations. Higher concentrations are less effective. TH-glucagon (1-N-alpha-trinitrophenylhistidine-12-homoarginine-glucagon) also reduces enzyme activity but does not lose activity at higher concentrations. The effects of the two hormones mimic closely their reported effects on phosphatidylinositol-4,5-bisphosphate breakdown. It is, thus, likely that the effect of glucagon on steroid metabolism is mediated via breakdown of this phospholipid. The calcium ionophore, A23187, had no effect on steroid metabolism whereas the phorbol ester 4 beta-phorbol-12-myristate-13-acetate (PMA) mimicked the effect of glucagon, showing that activation of protein kinase C but not Ca2+ mobilization may be involved in glucagon's action on hepatic steroid metabolism.
胰高血糖素在生理浓度下可降低离体大鼠肝细胞中类固醇代谢酶的活性。浓度较高时效果较差。TH-胰高血糖素（1-N-α-三硝基苯基组氨酸-12-高精氨酸-胰高血糖素）也能降低酶活性，但在较高浓度下不会丧失活性。这两种激素的作用与其报道的对磷脂酰肌醇-4,5-二磷酸分解的作用极为相似。因此，胰高血糖素对类固醇代谢的作用可能是通过这种磷脂的分解介导的。钙离子载体A23187对类固醇代谢无影响，而佛波酯4β-佛波醇-12-肉豆蔻酸酯-13-乙酸酯（PMA）模拟了胰高血糖素的作用，表明蛋白激酶C的激活而非Ca2+的动员可能参与了胰高血糖素对肝脏类固醇代谢的作用。
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