Effects of Epinephrine on Iodine and Intermediary Metabolism in Isolated Thyroid Cells¹

Abstract

Epinephrine, in concentrations of 1 and 10 μg/ml, greatly stimulated the organifica-tion of iodine as well as the formation of iodo-thyronines in suspensions of isolated thyroid cells. These effects were prevented by supplementing the incubation medium with methi-mazole 10−3M, but not with perchlorate 10−2M. Adrenochrome, the oxidative product of epinephrine, was equipotent in producing these effects. The action of both agents was blocked by phento-lamine, but not by propranolol. Reducing agents (ascorbate, sodium bisulfite) diminished the effects of epinephrine, but did not alter the effects of adrenochrome. Both epinephrine and adreno-chrome stimulated the adenyl cyclase activity of the isolated thyroid cells. Epinephrine stimulated the conversion of glucose-l-14C to 14CO2 and the incorporation of 14C-labeled mixed amino acids into the TCA-precipitable fraction of the thyroid cells. These actions resemble those of TSH; however, unlike TSH, epinephrine induced a depression of the incorporation of 32P-orthophos-phate into the phospholipids of the suspended cells. (Endocrinology87: 588, 1970)