Thyroid hormone metabolism in patients with liver cirrhosis, as judged by urinary excretion of triiodothyronine.

This study included 35 patients with liver cirrhosis, 23 patients with hyperthyroidism, 12 with hypothyroidism, and 2 with other endocrine disorders. In the various endocrine disorders an appreciable amount of triiodothyronine (T3) was excreted into the urine but the daily excretion was fairly constant in each patient. Urinary excretion of T3 was negligible or depressed in hypothyroidism, but increased with a rise in the serum level of T3. Serum and urinary T3 decreased in liver cirrhosis, but the serum thyroxine (T4) level was within the normal range. When the cirrhosis patients were divided into 3 groups according to the urinary excretion of T3, a decrease of urinary T3 was associated with a decrease in the serum levels of T3 and free T3. An increase of serum thyroid-stimulating hormone (TSH) either before or after injection of thyrotropin-releasing hormone (TRH) was inversely correlated with a decrease of serum and urinary T3. The decrease of serum and urinary T3 was correlated with the magnitude of lh a decrease in the serum levels of T3 and free T3. An increase of serum thyroid-stimulating hormone (TSH) either before or after injection of thyrotropin-releasing hormone (TRH) was inversely correlated with a decrease of serum and urinary T3. The decrease of serum and urinary T3 was correlated with the magnitude of lh a decrease in the serum levels of T3 and free T3. An increase of serum thyroid-stimulating hormone (TSH) either before or after injection of thyrotropin-releasing hormone (TRH) was inversely correlated with a decrease of serum and urinary T3. The decrease of serum and urinary T3 was correlated with the magnitude of liver damage as judged by indocyanine green retention and a decreased urinary excretion of cyclic adenosine 3',5'-monophosphate. In vitro experiments indicated that rat liver, as compared to the kidney, heart and skeletal muscle, strongly converts T4 to T3, but this activity is greatly reduced by liver damage induced by ligation of the bile duct. It is suggested that patients with liver cirrhosis are, to some extent, in a state resembling subclinical hypothyroidism because of inability of the liver to metabolize a sufficient amount of T3 from T4.