Forskolin Stimulation of 3, 5, W-Triiodothyronine Release from Perifused Rat Thyroids

Abstract

In a perifusion system in the presence of 3-isobutyl-1-methylxanthine, forskolin stimulated secretion of not only cAMP but also 3, 5, 3'-triiodothyronine (T₃) from rat thyroid glands. The increases in both cAMP and T₃ were dose-dependent at forskolin concentrations of 2.0×10^-7M to 2.0×10^-5M. After perifusion for 4 h, tissue concentrations of cAMP also increased as a result of forskolin treatment. Since forskolin is regarded as a specific activator of the cAMP generating system, this observed forskolin stimulation of T₃ secretion from perifused rat thyroid glands indicates that cAMP is involved in regulating thyroid hormone secretion.