[Induction of oocyte maturation at stages of incomplete vitellogenesis in toads and the starred sturgeon].

The intracellular injection of cytoplasm from the maturing oocytes of X. laevis and A. stellatus in oocytes of the same species which did not complete the vitellogenesis and are not able to mature under the effect of progesterone resulted in the disintegration of the germinal vesicle membrane in the oocytes of all sizes under study. In X. laevis the ability to mature under the effect of progesterone appears in the oocytes with the diameter over 1.1 mm. Cycloheximide inhibits the germinal vesicle membrane disintegration in the X. laevis oocytes, but not in those of A. stellatus. Cycloheximide inhibits the pseudogastrulation which was observed in the X. laevis oocytes with the diameter from 0.8 to 1.4 mm.