Tissue distribution, elimination and metabolism of [ 3H] - leukotriene C 4 in the American bullfrog, [formula omitted

Abstract

Tissue distribution, elimination, and metabolism of [ 3H] - leukotriene C 4 were studied at 2.5 hours after injection in the conscious and anesthetized American bullfrog, Rana catesbeiana . Conscious frogs were injected via the dorsal lymph sac or the sciatic vein. Anesthetized frogs were injected via the abdominal vein. The organs containing the greatest percent of injected radioactivity at 2.5 hours after injection were liver, small intestine and kidney. Route of injection and anesthesia appears to alter distribution and elimination of leukotrienes. [ 3H] - leukotrienes were eliminated into bladder water and bile. In addition, 7.8 ± 2.2 and 5.2 ± 2.5 percent of the injected radioactivity was found in the pan water bathing the ventral surface of the venously and dorsally injected conscious frogs, respectively, suggesting transfer of radioactivity across the skin. At 2.5 hours, polar metabolites represented 50% of the radioactivity found in liver, bile, and bladder water. These polar metabolites were determined to be 18-carboxy-19, 20-dinor-leukotriene E 4, 20-carboxy-leukotriene E 4, and 20-hydroxy-leukotriene E 4. Of the non-oxidized leukotrienes, bile contained mainly LTD 4 while bladder water contained primarily LTE 4. N-acetyl LTE 4 was not detected in any samples. The tissue distribution, elimination and metabolism of leukotrienes in the bullfrog was similar to mammalian studies and suggests evolutionary conservation of leukotriene processing.