Induction of vitellogenin synthesis in Xenopus laevis tadpoles.

Oestradiol induces vitellogenin synthesis in vitro in liver taken from Xenopus laevis tadpoles that are in late metamorphosis. Inducibility first appears at the end of prometamorphosis, and the response to oestradiol increases during the completion of metamorphosis. Oestradiol continuously present during development does not influence the stage at which tadpole liver becomes inducible. It seems that the acquisition of inducibility is part of the normal development of the liver, and independent of both the supply of oestrogen and the sex of the tadpole.