title: cAMP-dependent protein kinase regulates in ovo cAMP level of the Xenopus oocyte: evidence for an intracellular feedback mechanism.
abstract: Microinjection of cAMP-dependent protein kinase inhibitor (1.8 microM) increases the cAMP level of Xenopus oocyte. Its effect was observed in full-grown (stage VI) as well as in vitellogenic (stage IV) oocytes. In contrast the inhibitor I1 of protein phosphatase-1 blocks cAMP accumulation. Progesterone (1 microM) decreases the cAMP level in control and in PKI-treated oocytes of both stages. These results show that cAMP concentration is regulated by a cAMP-dependent phosphorylation indicating the presence of a feedback mechanism. The feedback control is disrupted when oocyte is induced to mature by progesterone.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D005246:Feedback; D005260:Female; D009865:Oocytes / Q000201:enzymology*; D010063:Ovum / Q000201:enzymology*; D010766:Phosphorylation; D011374:Progesterone / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D011374:Progesterone; D000242:Cyclic AMP; D011494:Protein Kinases