Fig. 10. Very few primordial follicles form in E16.5 fetal ovaries in culture and K252a has no effect on oocyte survival in this culture system. (Ai) The proportion of oogonia and oocytes in E16.5 ovaries cultured for four days and in P0 ovary without culture. (Aii) Further classification of oocytes into those contained in primordial and primary follicles, in E16.5 ovaries cultured for four days and in P0 ovary without culture. (B) The diameters of oocytes in E16.5 ovaries cultured in the presence or absence of 100 nM K252a.