INSULIN ACTION IN ISOLATED FAT-CELLS .2. EFFECTS OF DIVALENT-CATIONS ON STIMULATION BY INSULIN OF PROTEIN-SYNTHESIS, ON INHIBITION OF LIPOLYSIS BY INSULIN, AND ON THE BINDING OF I-125-LABELED INSULIN TO ISOLATED FAT-CELLS

被引:15
作者
AKHTAR, RA [1 ]
PERRY, MC [1 ]
机构
[1] UNIV LONDON CHELSEA COLL SCI & TECHNOL,DEPT BIOCHEM,BASIC MED SCI GRP,LONDON SW3 6LX,ENGLAND
基金
英国惠康基金;
关键词
(Fat cell); Antilipolysis; Ca[!sup]2+[!/sup; Insulin binding; Mg[!sup]2+[!/sup; Protein synthesis;
D O I
10.1016/0304-4165(79)90331-3
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The effects of omission of Ca2+ and Mg2+ from the incubation medium on three aspects of insulin action in isolated fat cells have been investigated. In the (Ca2+ + Mg2+)-free incubation medium incorporation of L-[14C]leucine into fat cell protein was reduced in the absence of insulin. Insulin stimulated L-[14C]-leucine incorporation only in the presence of added CaCl2 or MgCl2. Incubation of the cells in the (Ca2+ + Mg2+)-free medium reduced but did not abolish the ability of adrenaline to stimulate lipolysis or the ability of insulin to inhibit the adrenaline-stimulated lipolysis. Specific binding of 125I-labelled insulin to the fat cells was reduced in the absence of Ca2+ and Mg2+ but was not abolished, even in the presence of EDTA. Ca2+ was routinely the most effective divalent cation in supporting these aspects of insulin action, but similar responses were obtained with Mg2+, Sr2+ and Ba2+. Since insulin still binds to the cells under conditions in which some of the cellular effects of the hormone are abolished, it is suggested that divalent cations may have a role, either direct or indirect, in the processes linking the insulin-insulin receptor complex to certain effector systems in the cells. It is tentatively suggested that this action occurs at the level of the fat cell plasma membrane. © 1979.
引用
收藏
页码:117 / 127
页数:11
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