Activity of hepatic glucose phosphorylating and NADPH generating enzymes in Zucker rats.

The activities of hepatic enzymes involved in glucose phosphorylation and NADPH production were studied in male and female obese Zucker rats (fa/fa) and lean control animals (Fa/-). The fa/fa animals were heavier and had higher serum insulin levels than the lean rats. The glucokinase activity and the total glucose phosphorylation capacity were also higher in the obese animals. The activity of glucokinase correlated significantly with serum insulin levels. The glucose-6-phosphate phosphohydrolase activity was unchanged or slightly lowered in the obese rats. The activity of malic enzyme was elevated in the obese animals.