Specific Aim 2 will assess the effect of chromium supplementation on the insulin-stimulated activity of insulin receptor substrate-I-associated phosphatidylinositol 3-kinase in biopsies of muscle and fat tissue. This aim will also test the hypothesis that these physiological effects of chromium are mediated by alterations in the activity of insulin signaling. Understanding this mechanism may facilitate the design of even more effective strategies for improving insulin sensitivity.