Desensitization of Glucagon-Stimulated Adenylate Cyclase is Mediated by Stimulation of Inositol Phospholipid Metabolism
Desensitization is the process whereby responsiveness to a hormone or drug is reduced after repeated or prolonged exposure to that agonist. Although this phenomenon is widespread in biological regulation, the underlying molecular events have only recently begun to be defined. We have provided an initial characterisation of the molecular events leading to the rapid desensitization of glucagon-stimulated adenylate cyclase activity in rat hepatocytes. This, together with activation of specific cyclic AMP phosphodiesterases (1, 2), accounts for the transient rise in intracellular cyclic AMP concentrations that occurs when hepatocytes are challenged with glucagon (Fig.l).
KeywordsAdenylate Cyclase Inositol Phosphate Glucagon Receptor Rapid Desensitization Washed Membrane
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