Glucagon receptor binding, dissociation and degradation in rat liver plasma membranes studied by a microperifusion method
| Autor: | Robby A. Bacchus, Erik K. Frandsen |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
endocrine system
GTP' Glucagon Receptor Binding Peptide Glucagon Dissociation (chemistry) Receptors Gastrointestinal Hormone Mole Receptors Glucagon Animals Receptor Molecular Biology chemistry.chemical_classification Chemistry digestive oral and skin physiology Cell Membrane Rats Inbred Strains Cell Biology Rats Kinetics Membrane Biochemistry Liver Guanosine Triphosphate hormones hormone substitutes and hormone antagonists Peptide Hydrolases Protein Binding |
| Zdroj: | Biochimica et biophysica acta. 929(1) |
| ISSN: | 0006-3002 |
| Popis: | The association process of glucagon receptor binding in purified rat liver plasma membranes and prolonged incubation of the hormone-receptor complex at 30°C did not result in degradation of bound labelled glucagon. In contrast, up to 95% of the non-membrane-bound labelled glucagon was degraded. The rate of spontaneous dissociation of the glucagon-receptor complex was slow, and amounted to about 0.1% per min of that bound. GTP greatly enhanced the rate of dissociation. Half the maximal dissociation of the complex was effected by 10−5 mol/l of GTP under equilibrium binding conditions. At maximally effective concentrations of GTP, 80% of the glucagon-receptor complex was dissociated within 2 min. A microperifusion system for the perifusion of isolated plasma membranes was devised and used for the separation of labelled glucagon from the plasma membranes subsequent to a GTP-induced dissociation of the hormone-receptor complex. Rebinding of the dissociated peptide to fresh membranes showed that maximum binding ability was retained. The glucagon molecule was protected against degradation while bound to the receptor, indicating that the glucagon effector system is completely separate from the inactivating system(s) in isolated plasma membranes. Thus, the hormonal effect of glucagon could be exerted through the sequential interaction of each glucagon molecule with several receptors. |
| Databáze: | OpenAIRE |
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