Xenopus liver: ontogeny of estrogen responsiveness.

Estradiol-17 beta stimulates the synthesis of numerous proteins exported into the culture medium by Xenopus tadpole liver tissue obtained after stage 50 and throughout metamorphosis to stage 66. Although estrogen-induced vitellogenin can be detected as early as stage 54, it is a minor percentage of the exported proteins until after the completion of metamorphosis. In hepatic tissue obtained after metamorphosis, the hormone evokes the synthesis of vitellogenin specifically without affecting the labeling of other secreted proteins.