Thyroxine Turnover and Transport in Laennec's Cirrhosis of the Liver.

Studies of the metabolism of thyroxine in 14 cases of cirrhosis revealed a variety of deviations from normal. In addition to radiothyroxine turnover studies, determinations were made of the free thyroxine fractions and free thyroxine iodine concentrations in serum (magnesium precipitation method) as well as the maximal binding capacities of thyroxine-binding alpha globulin (TBG) and thyroxine-binding prealbumin (TBPA) by reverse flow paper electrophoresis in a glycine acetate system at pH 8.6.All cases of cirrhosis exhibited diminutions in TBPA capacities but their TBG capacities showed a wide scatter (13.4 to 41.6 mug/100 ml). The free thyroxine fraction was quite variable, with distinct elevations in nine of the 17 sera.The binding proteins appeared to be determinants of the free thyroxine fraction, which in turn, appeared to be a direct determinant of the half-time of turnover. These inferences did not exclude other possible factors including diminished hepatic uptake and metabolism of the hormone in liver disease.Despite considerable alterations in biological half-times, free thyroxine values, and binding proteins, it was remarkable that the absolute hormone disposal was normal in all 14 patients with cirrhosis.