Dehaye J P, Hughes B P, Blackmore P F, Exton J H
Biochem J. 1981 Mar 15;194(3):949-56. doi: 10.1042/bj1940949.
The effects of insulin on alpha-agonist (phenylephrine)- and [Arg8]vasopressin-induced Ca2+ and glucose release and mitochondrial Ca2+ fluxes in isolated perfused rat livers were examined. Insulin (6 nM) inhibited the ability of phenylephrine (1 and 0.5 microM) to elicit Ca2+ and glucose release, whereas it was without effect on vasopressin (10 and 2.5 nM) actions. Correspondingly, insulin inhibited the action of phenylephrine to induce a stable increase in mitochondrial Ca2+ uptake, but it did not affect the alteration caused by vasopressin. Phenylephrine and vasopressin caused transient increases in hepatocyte respiration. Insulin inhibited the effect of phenylephrine on this parameter, but not that of vasopressin. Insulin added alone did not alter any of the above parameters. It is concluded from these data that insulin does not alter cellular Ca2+ fluxes and respiration themselves, but selectively inhibits alpha-adrenergic stimulation of these processes. It is proposed that insulin acts either to inhibit binding of alpha-agonists to their specific plasma-membrane receptors or to alter generation and/or degradation of the putative alpha-adrenergic 'second messenger'. If this latter possibility is the case, then the alpha-adrenergic 'second messenger' must be different from the 'second messenger' of vasopressin.
研究了胰岛素对离体灌注大鼠肝脏中α-激动剂（去氧肾上腺素）和[精氨酸8]血管加压素诱导的Ca2+和葡萄糖释放以及线粒体Ca2+通量的影响。胰岛素（6 nM）抑制了去氧肾上腺素（1和0.5 microM）引起Ca2+和葡萄糖释放的能力，而对血管加压素（10和2.5 nM）的作用没有影响。相应地，胰岛素抑制了去氧肾上腺素诱导线粒体Ca2+摄取稳定增加的作用，但不影响血管加压素引起的变化。去氧肾上腺素和血管加压素导致肝细胞呼吸短暂增加。胰岛素抑制了去氧肾上腺素对该参数的影响，但不影响血管加压素的影响。单独添加胰岛素不会改变上述任何参数。从这些数据得出结论，胰岛素本身不会改变细胞Ca2+通量和呼吸，但选择性地抑制这些过程的α-肾上腺素能刺激。有人提出，胰岛素要么抑制α-激动剂与其特定质膜受体的结合，要么改变假定的α-肾上腺素能“第二信使”的生成和/或降解。如果是后一种情况，那么α-肾上腺素能“第二信使”必须与血管加压素的“第二信使”不同。
