Effect of cyclic AMP on the isolated human oocyte--cumulus complex.

Cyclic AMP (cAMP) is one of the key regulators of the resumption of oocyte meiosis (oocyte maturation) in several mammalian species. In this study we have examined the role for cAMP in regulation of spontaneous maturation of human oocytes. Oocytes were obtained in connection with gynaecological operations and cultured for 24 or 48 h. A significantly larger proportion (77%) of oocytes cultured in the presence of 1 mM dibuturyl-cAMP (dbcAMP) for 24 h were arrested in meiosis compared to oocytes cultured in control medium (25%). In addition, dbcAMP stimulated progesterone accumulation during 48 h of incubation and inhibited monolayer formation of the cumulus cells attached to the oocyte. The data presented in this study demonstrate that dbcAMP delayed the spontaneous maturation of human oocytes and stimulated progesterone production by the cumulus cells. These results indicate that cAMP may be important also for regulation of meiosis in human oocytes and confirm results obtained in other species.