Metyrapone block of thyroid-induced cardiomegaly

Cardiac wet and dry weight, adrenal weights, blood pressure and food consumption were measured in control male rats, rats fed 0.2% dried thyroid powder in the food, rats fed metyrapone (an inhibitor of adrenocortical 11-hydroxylase, Metopirone CIBA, 50 mg/rat per day) and both metyparone + dried thyroid. Metyparone markedly inhibited thyroid-induced cardiomegaly as well as the increase in adrenal weight. Myocardial dry weight and blood pressure differences between the various groups were not significant. The results supply further evidence of the existence of a relationship between the adrenal cortex and thyroid-induced cardiomegaly. Metyrapone also completely inhibited the post-thyroid drop in body weight.