Plasma glucose and insulin concentrations. Mean (± SE) plasma levels of glucose (A) and insulin (B), after LPS administration (4 ng/kg intravenously, T = 0 hours), during one of the following conditions: an L_insuE_gluc clamp (□), an L_insuH_gluc clamp (○), an H_insuE_gluc clamp (■), and an H_insuH_gluc clamp (●). Glucose was measured every 5 minutes; insulin was measured at time points as described in “Study protocol.”