RECOVERY OF BETA-RECEPTORS AND ADENYLATE-CYCLASE FROM DESENSITIZATION INDUCED BY SHORT-TERM HEAT EXPOSURE IN RAT PAROTID-GLANDS

1. The recovery of rat parotid beta-adrenergic receptors (beta-AR) and adenylate cyclase (AC) from heat (33-degrees-C)-induced desensitization was studied. 2. Down-regulated cell surface beta-AR and AC activity in response to isoprenaline (IPR) returned to the control level 120 hr after the termination of heat exposure. 3. However, beta-AR in parotid crude membranes increased over the control level for 48-120 hr. 4. Coupling between beta-AR and G protein(s) was attenuated at 120 hr. 5. These data suggest that beta-AR on the cell surface, but not those internalized, can transduce biological responses.