title: Pertussis toxin reverses Gpp(NH)p inhibition of basal and forskolin activated adipocyte adenylate cyclase.
abstract: Inhibition of basal adenylate cyclase by GTP or guanyl-5'-yl imidodiphosphate was abolished in membranes isolated from rat adipocytes previously incubated with pertussis toxin. Forskolin (0.1 microM) stimulated adenylate cyclase about 4-fold and inhibition of cyclase by GTP or guanyl-5'-yl imidodiphosphate was also abolished by pertussis toxin treatment of rat adipocytes. Forskolin (1 microM) increased adenylate cyclase activity at least ten-fold and the inhibitory effect of GppNHp was reduced but not abolished by pertussis toxin. In rabbit adipocytes, pertussis toxin reversed the inhibition of adenylate cyclase activity by GppNHp to the same extent as that by GTP in the presence of 1 microM forskolin. The present results indicate that pertussis toxin can reverse the inhibition of adipocyte adenylate cyclase by nonhydrolyzable GTP analogs as well as that by GTP.
mesh_terms: D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000273:Adipose Tissue / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology*; D005576:Colforsin; D004224:Diterpenes / Q000494:pharmacology*; D004789:Enzyme Activation; D005260:Female; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology; D037342:Pertussis Toxin; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D010566:Virulence Factors, Bordetella
chemical_list: D037361:Adenylate Cyclase Toxin; D001427:Bacterial Toxins; D004224:Diterpenes; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D037342:Pertussis Toxin; D000262:Adenylyl Cyclases; D007545:Isoproterenol