The effect of exercise associated with acute poisoning with potassium nitrate and sodium nitrite on the processes of intestinal absorption of D-xylose in rats.

The intestinal absorption of D-xylose was studied during acute poisoning of male Wistar rats receiving intragastrically potassium nitrate and sodium nitrite and small intestine perfusion with these compounds. The metabolic parameters, Na+/K(+)-ATPase, alkaline phosphatase, oxygen uptake, and lactic acid level, were assessed in the small intestine mucosa one hour after administration of these compounds. Exercise was demonstrated to reduce the intestinal absorption of D-xylose, to raise the level of lactic acid, and to increase the oxygen uptake by the small intestine mucosa, but caused no changes in the activity of Na+/K(+)-ATPase or alkaline phosphatase. Also, exercise failed to change the direction of the toxic effects of sodium nitrite but increased potassium nitrate toxicity as evidenced by reduced absorption of D-xylose from the intestine despite lack of changes of the enzymes Na+/K(+)-ATPase and alkaline phosphatase in the mucosa.