THE EFFECT OF TRIIODOTHYRONINE ON THE OXIDATIVE METABOLISM OF ERYTHROCYTES. I. CELLULAR STUDIES*†

Abstract

Human erythrocytes, incubated in the presense and absence of methylene blue, were used to delineate the enzymatic locus of action of the thyroid hormones. Triiodothyronine (TRITh) was added in vitro to intact cells and nicotinamide containing hemolysates and the O2 consumption was measured. Significant increases were noted in the presence of TRITh in both intact cells and hemolysates. Thyroxine in equivalent concentrations showed less stimulation while none was seen in the presence of diiodotyrosine, dinitrotyrosine, potassium iodide, and the chelating agents, Versene and sodium citrate. C14O2 production from glucose labeled in the 6-carbon position was stimulated by TRITh whereas that from glucose labeled in the 1-position was not. Glucose consumption was increased to a comparable degree. It was therefore concluded that TRITh stimulated the metabolism of glucose via the hexose monophosphate shunt in the human erythrocyte.