THYROXINE ANALOGUES AND CHOLESTEROL METABOLISM: THE RELATIVE EFFECTS OF VARIOUS THYROXINE DERIVATIVES ON GROWTH, OXYGEN CONSUMPTION AND TISSUE CHOLESTEROL CONCENTRATIONS IN THE RAT

Abstract

A number of thyroxine analogues have been tested for their relative effects on tissue cholesterol concentrations, oxygen consumption, and growth in the hypercholesterolemic rat. Of the compounds studied, diiodothyroacetic (diac) and diiodothyroformic acid (T2FA) appear to have the greatest effect in reducting tissue cholesterol concentrations without affecting growth or basal metabolism. Other derivatives such as tri- and tetraiodothyroacetic acids, triiodothyropropionic acid and tetraiodothyroformic acid have been shown by others to exert some preferential effect on tissue cholesterol concentrations. However, when compared on an equal molar basis in the present study, these compounds were not nearly as effective as diac and T2FA in lowering cholesterol levels.