Decreased hepatic glucose production and increased insulin sensitivity in PPARα-null mice. Wild-type and PPARα-null mice administered Wy14643 and fasted were analyzed by hyperinsulinemic clamp technique. (A) Hepatic glucose production under basal and hyperinsulinemic conditions. (B) Percentage of inhibition of hepatic glucose production by insulin. (C) Whole-body glucose utilization under basal and hyperinsulinemic conditions. (D) Percentage of stimulation of whole-body glucose utilization by insulin. Differences between genotypes were statistically significant for all variables except glucose utilization under hyperinsulinemic conditions. P < 0.05, Mann-Whitney U test. Error bars represent SEM.