Plasma concentration of corticosterone during Rana catesbeiana tadpole metamorphosis

Abstract

Plasma corticosterone concentrations have been studied in Rana catesbeiana tadpoles during metamorphosis. Corticosterone concentrations, determined by radioimmunoassay, in tadpole plasma were low prior to the onset of metamorphic climax (stage XX). The concentration of corticosterone in tadpole plasma from animals stages XXI to XXIV were significantly elevated above the concentration seen in animals of earlier stages. Adrenocorticotropin (ACTH) was able to stimulate an increase in plasma corticosterone in tadpoles of stages I to X. Triiodothyronine (T 3) treatment of tadpoles for 7 days caused a slight but insignificant increase in plasma corticosterone concentration over the concentration observed in control animals. The T 3-treated animals had, however, a significantly greater elevation of plasma corticosterone in response to ACTH than control animals.