The Xanthine Oxidase Activity of Rat Tissues.

Abstract

SummaryThe average xanthine oxidase activities in CmmO2/g dry weight/hour for adult rat tissues were: Liver 1862, small intestine 628, spleen 534, lung 479, kidney 135, stomach 42, skin 100-200, brain O, muscle O, testes O. Two-thirds of the total activity in the entire rat was in the liver.Methylene blue added to the Warburg flask in the aerobic determination increased the xanthine oxidase activity in liver, kidney, stomach and small intestine, but not in lung or spleen. Added xanthine oxidase was recovered quantitatively in the presence of lung, spleen and kidney; greater than added amounts of activity were recovered from liver and decreased amounts from small intestine. As the liver xanthine oxidase was depleted by a purified low protein diet, the small intestine lost about 2/3 of its activity, and lung lost about 1/2. Losses from the spleen and kidney were small. The entire rat lost 3/4 or more of its xanthine oxidase activity.