Cyclic AMP synthesis in Xenopus laevis oocytes: inhibition by progesterone

[alpha-32P]ATP was microinjected into Xenopus oocyte and neosynthesized cyclic AMP was isolated. Cholera toxin inhibited progesterone-induced maturation and stimulated after 3 h of preincubation the amount of neosynthesized cyclic AMP. Progesterone decreased the neosynthesis of cyclic AMP during the first hour following addition of the hormone.