Metabolism of thyroxine and triiodothyronine in patients with chronic granulomatous disease.

Normal human leukocytes can degrade thyroid hormones in vitro especially during phagocytosis. To test whether the leukocyte system plays a significant role in hormone economy in vivo, studies of the metabolism of labeled T4 and T3 granulomatous disease, whose leukocytes had earlier been shown to have a reduced ability to degrade the thyroid hormones. Hormone turnover rates in the 3 subjects were similar to those reported for normal children by various investigarors. Also, normal ratios between fecal and urinary excretion of radioactivey were observed, suggested that deiodination was the major route of hormone breakdown, as it is in normal subjects. Our interpretations of these findings are: 1) an intact leukocyte hormone degrading system is not essential for normal rates of thyroid hormone metabolism in vivo; 2) the leukocyte defect in chronic granulomatous disease is not accompanied by a general defect in mechanism for thyroid hormone degradation in other tissues.