Serum T4T3and Reverse T3During Treatment with Propranolol in Hyperthyroidism, L-T4Treated Myxedema and in Normal Man

Abstract
This study was conducted in 2 hyperthyroid groups (n = 13 and 11), in a group of normals (n = 9) and in a group of L-T4 [thyroxine] substituted patients (n = 7) with severe pretreatment hypothyroidism. Serum T4 did not change except in 1 hyperthyroid group in which a slight decrease was found. In all groups a significant fall in serum T3 [triiodothyronine] and a significant rise in serum reverse T3 were found. An expected increase in serum TSH in the normal and in the L-T4 substituted groups could not be demonstrated.