Abstract
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.
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- Aggerbeck M., Guellaen G., Hanoune J. The alpha-adrenergic mediated effect in rat liver. Correlation between [3H]-dihydroergocryptine binding to plasma membranes and glycogen phosphorylase activation in isolated hepatocytes. Biochem Pharmacol. 1980 Jun 15;29(12):1653–1662. doi: 10.1016/0006-2952(80)90120-3. [DOI] [PubMed] [Google Scholar]
- Blackmore P. F., Assimacopoulos-Jeannet F., Chan T. M., Exton J. H. Studies on alpha-adrenergic activation of hepatic glucose output. Insulin inhibition of alpha-adrenergic and glucagon actions in normal and calcium-depleted hepatocytes. J Biol Chem. 1979 Apr 25;254(8):2828–2834. [PubMed] [Google Scholar]
- Blackmore P. F., Brumley F. T., Marks J. L., Exton J. H. Studies on alpha-adrenergic activation of hepatic glucose output. Relationship between alpha-adrenergic stimulation of calcium efflux and activation of phosphorylase in isolated rat liver parenchymal cells. J Biol Chem. 1978 Jul 25;253(14):4851–4858. [PubMed] [Google Scholar]
- Blackmore P. F., Hughes B. P., Shuman E. A., Exton J. H. alpha-Adrenergic activation of phosphorylase in liver cells involves mobilization of intracellular calcium without influx of extracellular calcium. J Biol Chem. 1982 Jan 10;257(1):190–197. [PubMed] [Google Scholar]
- Bréant B., Keppens S., De Wulf H. Heterologous desensitization of the cyclic AMP-independent glycogenolytic response in rat liver cells. Biochem J. 1981 Dec 15;200(3):509–514. doi: 10.1042/bj2000509. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cantau B., Keppens S., De Wulf H., Jard S. (3H)-vasopressin binding to isolated rat hepatocytes and liver membranes: regulation by GTP and relation to glycogen phosphorylase activation. J Recept Res. 1980;1(2):137–168. doi: 10.3109/10799898009044096. [DOI] [PubMed] [Google Scholar]
- Keppens S., De Wulf H. The activation of liver glycogen phosphorylase by angiotensin II. FEBS Lett. 1976 Oct 1;68(2):279–282. doi: 10.1016/0014-5793(76)80453-x. [DOI] [PubMed] [Google Scholar]
- Keppens S., Vandenheede J. R., De Wulf H. On the role of calcium as second messenger in liver for the hormonally induced activation of glycogen phosphorylase. Biochim Biophys Acta. 1977 Feb 28;496(2):448–457. doi: 10.1016/0304-4165(77)90327-0. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Murphy E., Coll K., Rich T. L., Williamson J. R. Hormonal effects on calcium homeostasis in isolated hepatocytes. J Biol Chem. 1980 Jul 25;255(14):6600–6608. [PubMed] [Google Scholar]
- Vandenheede J. R., Keppens S., De Wulf H. The activation of liver phosphorylase b kinase by glucagon. FEBS Lett. 1976 Jan 15;61(2):213–217. doi: 10.1016/0014-5793(76)81040-x. [DOI] [PubMed] [Google Scholar]