title: Regulation of Ca2+ and cyclic AMP during the first meiotic division in amphibian oocytes by progesterone.
abstract: Progesterone appears to be the physiological inducer of meiosis in amphibian oocytes. In Rana pipiens, dl-propranolol mimics the action of progesterone and both agents have a common action in producing a rapid [45Ca] efflux and a fall in intracellular cAMP followed by nuclear breakdown. Comparison of the rate of hydrolysis of injected [3H]-cAMP and of the conversion of injected [3H]-ATP to [3H]-cAMP followed exposure to meiotic inducers and inhibitors indicates that adenylate cyclase and not phosphodiesterase is the rate-limiting step in regulating [cAMP]i in the oocyte. The results suggest that progesterone initiates the resumption of the meiotic divisions by down-regulation of membrane adenylate cyclase, possibly via Ca2+ release from specific membrane sites.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D005260:Female; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism*; D011374:Progesterone / Q000037:antagonists & inhibitors / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology; D011894:Rana pipiens
chemical_list: D011374:Progesterone; D011433:Propranolol; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000262:Adenylyl Cyclases; D002118:Calcium