Characteristics of the desensitization and resensitization of the cyclic AMP-independent glycogenolytic response in rat liver cells.

Vasopressin and alpha-adrenergic agonists were shown previously [Bréant, Keppens & De Wulf (1981) Biochem. J. 200, 509-514] to induce a heterologous, dose-dependent and receptor-mediated desensitization of the cyclic AMP-independent glycogenolytic response in isolated hepatocytes. The desensitized state of the hepatocytes can be preserved as long as the agonist is bound to its receptor. Conversely, washing the cells with a hormone-free buffer or displacement of the agonist from its receptor by a specific antagonist restores the responsiveness. The desensitization and its reversibility (i.e. resensitization) are obtained within minutes. The desensitization can be clearly elicited at temperatures as low as 5 degrees C, whereas the glycogenolytic response and the enhancement of the 45Ca flux are only obtained above 15 degrees C; the resensitization requires even higher temperatures. A tentative model is proposed to account for the observed effects.