Impairment of insulin-induced vasodilation is associated with muscle insulin resistance in type 2 diabetes

To clarify the association between the actions of insulin on the vascular w all and on the muscles in diabetes, we evaluated insulin-mediated vasodilat ion and muscle glucose uptake simultaneously using the euglycemic hyperinsu linemic glucose clamp technique and the calculation of total peripheral vas cular resistance (TPR) from arterial pulse wave analysis in 19 Japanese pat ients with type 2 diabetes who had no signs of atherosclerosis. During the clamp study, the plasma norepinephrine (NE) level and plasma renin activity (PRA) increased without showing any significant correlation to the glucose infusion rate (GIR); a marker of muscle insulin sensitivity, and no change s of other plasma vasoactive hormone levels were observed. TPR decreased ov er time during the clamp study. The decrease of TPR from baseline was 0.88 +/- 0.02 at 1 h (mean +/- S.E.M., P < 0.01) and 0.79 +/- 0.03 at 2 h (P < 0 .01), and the relative change in TPR from baseline was negatively correlate d with GIR (r = -0.48 at 1 and 2 h; both P < 0.05). Our results suggest tha t there is also insulin resistance in the vascular wall, and this phenomeno n may be associated with muscle insulin resistance in type 2 diabetes. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.