A phospho-oligosaccharide mimics insulin action on glycogen phosphorylase and pyruvate kinase activities in isolated rat hepatocytes.
A phospho-oligosaccharide which is the polar head group of a novel insulin-sensitive glycophospholipid has recently been involved in insulin action. We have investigated the insulin-like effects of this phospho-oligosaccharide on both glycogen phosphorylase a and pyruvate kinase activities of hepatocytes incubated in the presence of glucagon (0.1 nM). Similarly to insulin, the phospho-oligosaccharide antagonized glucagon-dependent activation of glycogen phosphorylase, as well as the inactivation of pyruvate kinase caused by this hormone. The antagonistic action of the phospho-oligosaccharide on glucagon effects was dose-dependent. Furthermore, it partially antagonized glucagon-stimulated cyclic AMP levels. These results support the hypothesis that this phospho-oligosaccharide mediates at least some insulin actions in hepatocytes.
Alvarez
J F
JF
Cabello
M A
MA
Felíu
J E
JE
Mato
J M
JM
D000818:Animals; D005934:Glucagon / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000032:analysis / Q000187:drug effects / Q000201:enzymology*; D009844:Oligosaccharides / Q000494:pharmacology*; D010762:Phosphorylase a / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006005:Phosphorylases / Q000378:metabolism*; D011770:Pyruvate Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D009844:Oligosaccharides; D005934:Glucagon; D010762:Phosphorylase a; D006005:Phosphorylases; D011770:Pyruvate Kinase