Figure 1.

Experimental protocol—during visit 1 (top), a fasting basal euglycemic period was followed by a hyperglycemic clamp with variable glucose infusion to attain a target of basal +5.5 mmol/L. During visit 2 (bottom), performed at least 15 days after the first visit, a fasting basal euglycemic period was followed by a hyperinsulinemic euglycemic clamp with variable insulin and variable glucose infusion; individual insulin levels were matched to the levels attained during the hyperglycemic clamp of visit 1. Magnetic resonance imaging (MRI)/magnetic resonance spectroscopy (MRS) scans were performed during each of the four plasma glucose/insulin periods, indicated by boxes at the bottom of the figure. The means ± standard error values of plasma glucose are indicated for each visit and condition.