Insulin and Insulin-like Growth Factor-1 Modulation of Glucose Transport in Arterial Smooth Muscle Cells: Implication of GLUT-4 in the Vasculature

Insulin modulates many physiological processes in vascular smooth muscle cells (VSMC) such as con tractility, proliferation, and ion homeostasis. How ever, hormonal modulation of glucose transport has not been explored in pure populations of these cells. This study demonstrates that insulin and in sulin-like growth factor-1 (IGF-1) increase glucose transport in a7r5 clonal and freshly prepared Spra gue-Dawley aortic (SDa) VSMC. In a7r5 cells, physiologic ( 1 0 ~ 1 2 to 1 0 ~ 9 mol/L) insulin concentra tions increase transport by 8 % to 15%, whereas su-praphysiologic concentrations (10 ~ 9 to 1 0 " 6 mol/L) increase transport by up to 60 % (P <.05 ν no in crease over all concentrations tested). In SDa cells, insulin was more potent, displaying maximu