Reduction of Serum Cholesterol by Sodium Dextro-Thyroxine

Abstract

Introduction Many attempts to characterize dextro-thyroxine have been made with racemic mixtures of the thyroxine optical isomers. This actually concealed the characteristics of the dextro-thyroxine. The known change produced by levo-thyroxine alone was subtracted from the result obtained by administering both isomers. The remainder was assumed to be the independent effect of dextro-thyroxine. Interest was centered on what was assumed to be the principal, if not the only function of the thyroid hormone, the ability to increase oxygen consumption. It now seems that thyroxine, or one of its derivatives, affects many diverse processes in the body directly. Dextro-thyroxine has very little calorigenic potency as compared to levo-thyroxine or, especially, levo-triiodo-thyronine, but seems to be much stronger in cholesterol reduction than either of these in inverse ratio to heat production—i.e., an amount of dextro-thyroxine that does not increase the basal metabolic rate, at either athyreotic or euthyroid levels, has a pronounced