Effect of colchicine and allopurinol on uricogenesis. II. Effect of administration to chicks and mice

Abstract

Colchicine injected intraperitoneally to chicks and mice induces a decrease in liver xanthinedehydrogenase activity which is not recovered by dialysis of the hepatic ho- mogenates. The injection of allopurinol into young chicken also greatly reduces the activity of their hepatic and kidney enzymes, although it is partially recovered by dialysis of the homogenates. The presence of allopurinol in the animal organism induces a marked decrease of uric acid levels in liver, kidney and serum, accompanied by an increment of hypoxanthine. These effects of the drug tend to decrease with time and completely disappear 24 hours after the injection.

Colchicine inhibits the in vitro dehydrogenation of hypoxanthine to xanthine cata- lyzed by xanthinedehydrogenase of chicken liver homogenates, and also the transfor- mation of adenine into uric acid. Neither colchicine níƒor allopurinol interfere with the conversión into hypoxanthine of both inosine and adenosine. Colchicine does not inhibit the de novo biosynthesis of hypoxanthine performed by pigeon liver homo­ genates, starting from glycine, fórmate and carbón dioxide.