Metabolism of Iodine-131-Labeled Thyroxine-Binding Prealbumin in Man

The metabolism of (131)I-labeled thyroxine-binding prealbumin was studied in four normal subjects and in five hospitalized patients with nonthyroidal disease. The average half-time of total-body thyroxine-binding prealbumin, calculated on the basis of a two-compartmental model, was 1.90 daysin normal subjects. Increased fractional degradation or diminished synthesis, or both, contributed to the depression of thyroxine-binding prealbumin in the serum of patients with nonthyroidal disorders.