大鼠肝脏中的两种激素反应性腺苷酸环化酶。

Two types of hormone-responsive adenylate cyclase in the rat liver.

作者信息

Yamatani K, Sato N, Wada K, Suda K, Wakasugi K, Ogawa A, Takahashi K, Sasaki H, Hara M

机构信息

Third Department of Internal Medicine, Yamagata University School of Medicine, Japan.

出版信息

Biochim Biophys Acta. 1987 Nov 12;931(2):180-7. doi: 10.1016/0167-4889(87)90205-9.

DOI:10.1016/0167-4889(87)90205-9

PMID:2444265

Abstract

We have demonstrated the existence of two types of hormone-responsive adenylate cyclase in the isolated perfused rat liver. One, less abundant, is linked to glycogenolysis and the other is not. Glucagon stimulates mainly the glycogenolysis-linked fraction and, to a lesser extent, the fraction which is not linked to glycogenolysis. The suppressive effect of insulin is specific for the glucagon-responsive adenylate cyclase and is inhibited by 3-isobutyl-1-methylxanthine (IBMX). However, this mechanism can explain only partly the ability of insulin to suppress glycogenolysis, and is not observed when cAMP is increased sufficiently by glucagon. Secretin-responsive adenylate cyclase is not linked to glycogenolysis and is suppressed specifically by oxymetazoline. The capacity of this suppressive effect is large and not inhibited by IBMX. These results suggest that there is a functional compartmentalization of cAMP within the hepatocyte or among hepatocytes.

摘要

我们已经证实在离体灌注的大鼠肝脏中存在两种激素反应性腺苷酸环化酶。一种含量较少，与糖原分解有关，另一种则无关。胰高血糖素主要刺激与糖原分解相关的部分，对与糖原分解无关的部分刺激作用较小。胰岛素的抑制作用对胰高血糖素反应性腺苷酸环化酶具有特异性，并被3 - 异丁基 - 1 - 甲基黄嘌呤（IBMX）抑制。然而，这种机制只能部分解释胰岛素抑制糖原分解的能力，当胰高血糖素使环磷酸腺苷（cAMP）充分增加时则未观察到这种情况。促胰液素反应性腺苷酸环化酶与糖原分解无关，并被羟甲唑啉特异性抑制。这种抑制作用的能力很强，且不受IBMX抑制。这些结果表明在肝细胞内或肝细胞之间存在cAMP的功能分区。