Leukotriene C4 elimination and metabolism in man.

Three doses of radiolabeled leukotriene C4 (0.2 to 15 muCi) were infused into three subjects to investigate its metabolism and routes of elimination during 4 days. Between 12% and 20% of the infused dose was recovered in the urine within 24 hours, of which a substantial and relatively constant proportion (4.1% to 6.3% total dose) appeared as leukotriene E4 (LTE4), mainly in the first 4 hours. Polar omega-oxidation products, N-acetyl LTE4, and tritiated water were also present. Fecal elimination accounted for a further 30% to 40% of the infused dose. In the absence of altered metabolism or biliary excretion, urinary LTE4 may be a useful measure of whole body production of the cysteinyl leukotrienes.