Further Studies on Anti-Thyroxine Effects of Various Compounds.

Abstract

The study of compounds inhibiting the peripheral metabolic action of thyroxine in thyroidectomized rats has been extended to such substances as vit. A, vit. B12, cholesterol and a series of aliphatics and aromatics carrying the 3,5-diiodo-4-hydroxy-phenyl grouping. The compounds found capable of producing approx. 50% inhibition were vit. A, beta-carotene, cholesterol, butyl-3,5-diiodo-4-hydroxybenzoic acid, and alpha-methyl-beta-(3,5-diiodo-4-hydroxyphenyl)-propionic acid. Several other substances were found to be less active than these. No compound tested was found clearly active as a thyroxine antagonist at an inhibitor:thyroxine ratio of less than 300.