Effect of Prolonged PDE-5 Inhibition on Insulin Signaling in Skeletal Muscle.

Participants enrolled in the study titled " Renin-angiotensin and fibrinolysis interaction in humans: effect of long-term PDE5 inhibition on glucose Homeostasis, (Specific aim 2)" will be offered the opportunity to participate in this sub-study. We will obtain skeletal muscle biopsies from 16 subjects who are enrolled in specific aim 2. Eight subjects will be in the sildenafil group and 8 subjects will be in the placebo group.