Phosphorylation control by insulin in adipocytes is interfered with at a post-receptor step by phosphoinositol and glucosamine.
Inositol-phosphates, glucosamine and glucose-6-phosphate blocked the effects of insulin on target protein phosphorylation in adipocytes, but the unsubstituted or sulphated derivatives of inositol or of glucose, or N-acetyl-glucosamine were without effect. The insulin stimulated tyrosine phosphorylation of the insulin receptor was not affected. The sugar-phosphates inositol-phosphate and glucose-6-phosphate did not enter into the cells. They also blocked the insulin-like effects of a potential second messenger of insulin, a phospho-oligosaccharide (POS), which has previously been shown to mimic the effects of insulin on protein phosphorylation in intact cells.
Department of Physiological Chemistry, University of Lund, Sweden.
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Strålfors
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Alemany
D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D005944:Glucosamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000494:pharmacology*; D007328:Insulin / Q000502:physiology*; D008297:Male; D009844:Oligosaccharides / Q000494:pharmacology; D010766:Phosphorylation; D019000:Phosphotyrosine; D051381:Rats; D011972:Receptor, Insulin / Q000378:metabolism*; D013403:Sugar Phosphates / Q000494:pharmacology; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D007295:Inositol Phosphates; D007328:Insulin; D009844:Oligosaccharides; D013403:Sugar Phosphates; D019000:Phosphotyrosine; D014443:Tyrosine; D011972:Receptor, Insulin; D005944:Glucosamine