title: Characterization of the adenylate cyclase of the rat corpus luteum during luteolysis induced by a prostaglandin F2 alpha analogue.
abstract: Rats with superluteinized ovaries were injected with the prostaglandin F2 alpha (PGF2 alpha) analogue cloprostenol to induce luteolysis. The treatment led to decreased adenylyl cyclase response to hCG and isoproterenol in ovarian homogenates while the response to forskolin remained unchanged indicating that the catalytic unit of the enzyme was not affected by the treatment. The activation of adenylyl cyclase by Mg2+ or the non-hydrolysable guanosine triphosphate (GTP) analogue guanosine-5'-(beta,gamma-imido)-triphosphate (GMP-P(NH)P) was not altered by the treatment with cloprostenol. Both basal and hormone-stimulated adenylyl cyclase activity increased with increasing concentration of GMP-P(NH)P. Unstimulated adenylyl cyclase continuously increased with increasing concentrations of Mg2+. The same applied to forskolin. The dependence of the adenylyl cyclase stimulation by hCG and isoproterenol on Mg2+ was complex. It is postulated that PGF2 alpha induces the attenuation of ovarian adenylyl cyclase by a modification in the coupling of the hormone-receptor to the N beta-component of the adenylyl cyclase complex while the catalytic unit remains unchanged.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D003008:Cloprostenol / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology; D003338:Corpus Luteum / Q000201:enzymology* / Q000378:metabolism; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008186:Luteolytic Agents / Q000494:pharmacology*; D008274:Magnesium / Q000494:pharmacology; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*; D012314:RNA Cap Analogs / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D008186:Luteolytic Agents; D011461:Prostaglandins F, Synthetic; D012314:RNA Cap Analogs; D005576:Colforsin; D003008:Cloprostenol; C023450:2'-O-methylguanosine 5'-triphosphate; D006160:Guanosine Triphosphate; D000262:Adenylyl Cyclases; D008274:Magnesium; D007545:Isoproterenol