LOCAL REGULATORY EFFECTS OF ACTIVIN-A AND FOLLISTATIN ON MEIOTIC MATURATION OF RAT OOCYTES

Activin A and follistatin identified in follicular fluids have been shown to regulate follicular development. Activin A, in a dose responsive manner, increased the percentage of germinal vesicle breakdown that served as a marker for the resumption of meiosis of oocytes in vitro, especially these obtained from immature follicles. This effect of activin A was inhibited by the activin-binding protein, follistatin. Follistatin alone exerted an inhibitory effect on oocyte maturation. Reverse transcription and polymerase chain reaction revealed the expression of activin βA and activin type IIA receptor gene transcripts in the oocytes. Activin A, along with follistatin, appears to play a local regulatory role in the meiotic maturation of rat oocytes. © 1993 Academic Press, Inc.