RAPID STIMULATION BY VASOPRESSIN, OXYTOCIN AND ANGIOTENSIN .2. OF GLYCOGEN DEGRADATION IN HEPATOCYTE SUSPENSIONS
RAPID STIMULATION BY VASOPRESSIN, OXYTOCIN AND ANGIOTENSIN .2. OF GLYCOGEN DEGRADATION IN HEPATOCYTE SUSPENSIONS
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DOI：
10.1042/bj1720311
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发表时间：
1978-01-01
影响因子：
4.1
通讯作者：
WHITTON, PD
中科院分区：
文献类型：
--
作者：
HEMS, DA;RODRIGUES, LM;WHITTON, PD
The hormonal control of glycogen breakdown was studied in hepatocytes isolated from livers of fed rats. Glucose release was stimulated by [8-arginine]vasopressin (10 pM-10 nM), oxytocin (1 nM-1 .mu.M) and angiotensin II (1 nM-0.1 .mu.M). These responses are all at least as sensitive to hormone as is glucose output in the perufused rat liver. The effect of these 3 hormones on glucose release was critically dependent on extracellular Ca2+, unlike that of glucagon. Half-maximal restoration of the vasopressin response occurred if 0.3 mM-Ca2+ was added back to the incubation medium. Glycogen breakdown was more than sufficient to account for the glucose released into the medium, in the absence or presence of hormones. Lactate release by hepatocytes was not affected by vasopressin, but was inhibited by glucagon. If Ca2+ was omitted from the extracellular medium, vasopressin stimulated glycogenolysis, but not glucose release. The phosphorylase a content of hepatocytes was increased by vasopressin, oxytocin and angiotensin II; minimum effective concentrations were 0.1 pM, 0.1 nM and 10 pM respectively. This response was also dependent on Ca2+. Hepatocytes can respond to low concentrations of vasopressin and angiotensin II, i.e., these effects are likely to be relevant in the intact animal. The role of extracellular Ca2+ in the effects of these hormones on hepatic glycogenolysis and glucose release is discussed.
