The effect of PRED with or without concomitant EXE infusion on plasma glucose (A), insulin (B), C-peptide (C), and glucagon (D) levels during the meal challenge. PRED increased AUCG, which was prevented by EXE (A), despite lower insulin and C-peptide levels (B,C). EXE infusion reduced postprandial glucagon levels compared with PRED (D). Mean ± SEM shown. Black solid line with closed squares: PLB+SAL; gray intersected line with closed circles: PRED+SAL; black dotted line with open circles: PRED+EXE.