Fig. 1.

Study timeline. All subjects completed 30 min of resting baseline followed by a 90-min hyperinsulinemic, euglycemic infusion. Steady-state measures were collected at baseline and during the last 30 min of the insulin infusion. At this time, subjects breathed room air freely for 15 min and then were acutely exposed to hyperoxia. An initial group of subjects (protocol 1) completed a saline visit only. A second group of individuals (protocol 2) participated in 2 identical study visits randomized to placebo (saline) or intravenous dopamine. Dopamine/saline was infused for 15 min before collection of baseline measurements until the end of the 90-min insulin infusion. FFM, fat-free mass.