Abstract
Insulin treatment of isolated liver plasma membranes induced the release of 5'-nucleotidase and alkaline phosphatase. This effect was maximal at physiological hormone concentrations, being 36% and 17% for 5'-nucleotidase and alkaline phosphatase respectively, and was fully mimicked by the phosphatidylinositol specific phospholipase C (PI-PLC), thus confirming the presence of a glycosylphosphatidylinositol anchoring-system for these exofacial enzymatic proteins. The complete inhibition of insulin dependent enzyme release by neomycin is strongly supportive of an involvement of membrane-located PI-PLC activity. In addition, the insulin-like effect on enzyme release induced by the GTP non-hydrolysable analog, GTP-gamma-S, and its sensitivity to the pertussis toxin are in favour of a mediatory role exerted by the G proteins system, in the transduction of some actions of insulin.
Publication types
-
Comparative Study
-
Research Support, Non-U.S. Gov't
MeSH terms
-
5'-Nucleotidase / metabolism*
-
Alkaline Phosphatase / metabolism*
-
Animals
-
Cell Membrane / drug effects
-
Cell Membrane / metabolism
-
Dose-Response Relationship, Drug
-
GTP-Binding Proteins / metabolism
-
Glycosylphosphatidylinositols
-
Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
-
Insulin / pharmacology*
-
Insulin Antagonists
-
Liver / drug effects*
-
Liver / metabolism
-
Male
-
Neomycin / pharmacology
-
Pertussis Toxin
-
Phosphatidylinositol Diacylglycerol-Lyase
-
Phosphatidylinositols / analysis*
-
Phosphoinositide Phospholipase C
-
Phosphoric Diester Hydrolases / pharmacology
-
Polysaccharides / analysis*
-
Rats
-
Rats, Wistar
-
Virulence Factors, Bordetella
Substances
-
Glycosylphosphatidylinositols
-
Insulin
-
Insulin Antagonists
-
Phosphatidylinositols
-
Polysaccharides
-
Virulence Factors, Bordetella
-
Guanosine 5'-O-(3-Thiotriphosphate)
-
Pertussis Toxin
-
Alkaline Phosphatase
-
5'-Nucleotidase
-
Phosphoric Diester Hydrolases
-
Phosphoinositide Phospholipase C
-
GTP-Binding Proteins
-
Phosphatidylinositol Diacylglycerol-Lyase
-
Neomycin