In vivo effect of nitrogen dioxide on the activities of glycolytic enzymes in red blood cells of rats

Abstract

The effects of short-term exposure to NO 2 on the glycolytic enzymes of rat red cells were examined. Exposure to 10 ppm NO 2 resulted in decrease in activities of pyruvate kinase (PK) and phosphofructokinase (PFK) at day 1 and then increased progressively. Exposure to 4 ppm NO 2 caused progressive increases in these enzyme activities from the first day. At day 5, the PK and PFK activities of exposed animals became higher than those of controls followed by decreasing to the control level at day 10. Red blood cells were fractionated according to their ages. The specific activities of PK and PFK decreased as red cells became older. 7-day exposure to 4 ppm NO 2 resulted in elevation of PK and PFK activities in all red cell subfractions. In addition, the amount of youngest cells decreased concomitant with increases in those of older cells. These findings suggest that NO 2 inhalation enhances red cell turnover.