Induction of maturation (meiosis) in Xenopus laevis oocytes by three organomercurials.

Three organomercurials, p-hydroxymercuribenzoate, p-hydroxymercuriphenylsulfonate, and mersalyl, induce maturation (meiosis) in a large percentage (20-100 percent) of Xenopus laevis oocytes. Maturation takes place even when the follicle cells which surround the oocytes have been withdrawn. Organomercurial- and progesterone-induced maturations have many features in common: they do not occur when the inducer is injected into the oocytes, they require the presence of Ca++ in the medium, they are inhibited by cycloheximide but not by actinomycin D. In both cases, the maturation producing factor and the pseudomaturation inducing factor are produced. Organomercurial-treated oocytes react normally to activating stimuli; their protein synthesis increases, but uptake of amino acids is strongly inhibited. Progesterone and p-hydroxymercuriphenyl-sulfonate act synergically in inducing maturation. The main difference between the two agents is that p-hydroxymercuriphenylsulfonate must act for several hours, whereas, short contact with progesterone is sufficient to induce maturation.