BOVINE ACTIVIN A DOES NOT AFFECT THE IN-VITRO MATURATION OF BOVINE OOCYTES

The effect of recombinant bovine activin A on the in vitro maturation of bovine oocytes was investigated. Culture of cumulus enclosed bovine oocytes in the presence of activin at the concentration of 100 or 500 ng/ml did not change the proportion of oocytes in which germinal vesi cle breakdown had occurred at 4 and 7 h after the onset of culture. Ac tivin had also no effect on the progression of maturation to the M II stage. The transient inhibition of germinal vesicle breakdown by 10 mM dibutyryl cyclic AMP was not affected by the addition of activin A at the onset of culture. Radiolabeling with S-35-methionine at 4 h and a t 18 h after culture in the presence or absence of activin A did not s how any effect of activin either on the total incorporation of radiola bel into acid precipitable material or on the protein synthesis patter ns obtained after SDS-PAGE.