title: Beta-adrenergic regulation of Sertoli cell adenylyl cyclase: desensitization by homologous hormone.
abstract: Incubation of Sertoli cell-enriched cultures with D,L-isoproterenol caused a time- and concentration-dependent, homologous desensitization of isoproterenol-responsive adenyl cyclase, whereas the response to FSH was unaffected. Half-maximal desensitization was achieved within 1 h of preincubation, after which a more gradual loss of response was observed. Preincubation of Sertoli cells for 24 h with increasing concentrations of D,L-isoproterenol demonstrated that the concentration required to obtain half-maximal densensitization was approximately 10-fold lower than the Km for activation of adenylyl cyclase. The function of the guanine nucleotide regulatory component (N-component) of the adenylyl cyclase complex in hormonally desensitized Sertoli cells, as evaluated by activation of adenylyl cyclase by GTP, GMPP(NH)P, fluoride and Mg2+, was not affected by the hormone pretreatment. Preincubation of Sertoli cells with a high concentration of dbcAMP (10(-3) M) for 24 h was associated with a 45% reduction in adenylyl cyclase activation by both FSH and isoproterenol. Also in this case fluoride- and GTP-stimulated adenylyl cyclase activities were normal. However, the effects of dibutyryl cyclic AMP occurred much more slowly than agonist-induced desensitization, indicating that cAMP may not be the primary mediator of homologous desensitization of Sertoli cell adenylyl cyclase by isoproterenol.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005459:Fluorides / Q000494:pharmacology; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012708:Sertoli Cells / Q000201:enzymology*
chemical_list: D011943:Receptors, Adrenergic, beta; D003994:Bucladesine; D006160:Guanosine Triphosphate; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D007545:Isoproterenol; D005459:Fluorides