Calmodulin is involved in the first step of oocyte maturation: effects of the antipsychotic drug fluphenazine and of anticalmodulin antibodies on the progesterone-induced maturation of xenopus laevis oocyte.

Specific anticalmodulin antibodies were microinjected into full-grown Xenopus laevis oocyte, and it is shown that in ovo blockade of the complex Ca2+-calmodulin accelerates the kinetics of progesterone-induced maturation, even though the molar ratio of antibody binding sites to total calmodulin was only 0.16. Addition of 200 microM fluphenazine to the oocyte incubation medium resulted in a similar acceleration of steroid-induced maturation. Neither protein kinase inhibitor (PKI) nor maturation promoting factor (MPF)-induced maturation are affected either by the antipsychotic drug or by anticalmodulin antibodies; this result suggests that the adenylate cyclase system may be the target for anticalmodulin antibodies and fluphenazine effects.