Increased serum thyroid hormone binding and decreased free hormone in chronic active liver disease.

To determine whether chronic inflammatory disease of the liver increases serum thyroid hormone binding, we measured tri-iodothyronine resin binding ratios in nine patient with primary biliary cirrhosis and in nine with chronic active hepatitis. In each group, the average binding ratio was about 50 per cent higher than in control subjects. Thyroxinebinding globulin, measured by immunoassay in three patients, was elevated. Although average total thyroxine and tri-iodothyronine were increased slightly, the corresponding free hormone concentrations were lower than controls, probably because of decreased thyroid function associated with the high incidence of autoimmune thyroiditis in nonalcoholic (autoimmune) liver disease. Thyroid autoantibodies were found in 13 patients. Impaired hepatic thyroxine-to -tri-iodothyronine conversion may have contributed to the low free tri-iodothyronine. Thyrotropin was elevated in four patients. Because of increased serum thyroid hormone binding in these patients total thyroxine and tri-iodothyronine concentration can be normal despite hypothyroidism.