[Effect of cycloheximide on the disintegration of the germinal vesicle membrane and on changes in the cortical layer in oocytes of the clawed toad and the starred sturgeon during maturation on exposure to active cytoplasm].

There was studied the effect of cycloheximide on the changes in the X. laevis and A. stellatus oocytes maturing under the influence of active cytoplasm, taken from the maturing oocytes, and, in the control series, under the influence of progesterone. The suppression of protein synthesis in the X. laevis oocytes by means of cycloheximide by 90--95% did not prevent the amplification of the factor of disintegration of the germinal vesicle membrane after 4 and 5 transfers of the active cytoplasm through the cycloheximide-treated oocytes; no pseudogastrulation was observed in such oocytes. Under the similar suppression of protein synthesis in the A. stellatus oocytes, the germinal vesicle did not break down already after the first injection of active cytoplasm; such oocytes acquried, however, the ability of cortical reaction. The cycloheximide-treated oocytes of both the species did not mature under the effect of progesterone. The fully grown A. stellatus oocytes matured after the injection of active cytoplasm from the mature X. laevis oocytes.