Augmentation of Nuclear Binding Capacity for Triiodothyronine by Aldosterone in Tadpole Tail

Abstract

Effect of aldosterone on T₃-binding to the nuclear fraction of the tail of toad tadpoles was investigated in vitro. T₃-binding was increased by adding aldosterone to the incubation medium. Scatchard analysis revealed that aldosterone (3.4×10^-6M) increased the maximum binding capacity by 40% and that the steroid scarcely affected the value of dissociation constant. Elevation of thyroid hormone sensitivity in the presence of corticoids seems to be closely related to the corticoid-induced increase in nuclear binding capacity for thyroid hormones.