Glycolytic enzyme activities in liver, heart and gastrocnemius of Sprague-Dawley and Wistar rats: effect of high sucrose diet

1. Pyruvate kinase, phosphofructokinase, and glucophosphate isomerase activities were measured in liver, heart and gastrocnemius of Wistar and Sprague-Dawley rats. 2. Enzyme activities were significantly lower in tissues of Wistar rats except for pyruvate kinase in gastrocnemius. 3. Sensitivities of pyruvate kinase and phosphofructokinase to inhibition by alanine and citrate differed in these two strains except for pyruvate kinase in gastrocnemius. 4. Phosphofructokinase sensitivity to citrate was greater in the three Wistar tissues. 5. Activities of liver enzymes were more responsive to a high sucrose diet in Wistar rats. 6. Heart pyruvate kinase and phosphofructokinase exhibited modest increases in activity with a high sucrose diet.