Iodothyronines in human bile

Bile was collected from 7 patients after cholecystectomy with routine T-tube drainage of bile duct postoperatively. In all patients reported, the total volume of bile collected was more than 500 ml which was considered to be close to the volume of bile excreted by the liver during the 24 h collection period. The excretion of total thyroxine (T4), triiodothyronines (T3 and rT3) and diiodothyronines (3,3'-T2, 3,5-T2 and 3'.5'-T2) was estimated with the aid of specific radioimmunoassay described previously. It was found that the total amount of T4 corresponded to its content in about 100 ml plasma, while corresponding figures for triiodothyronines were about 1000-1500 ml and these for diiodothyronines about 10-15 liters. It was concluded that in man the biliary excretion of iodothyronines appears to be of much less importance for their total body balance than in rats.