We propose to determine the acute metabolic effects of intensive insulin therapy when administered to AKI patients with a particular focus on its effects on protein metabolism. We hypothesize that the degree of insulin resistance correlates with protein catabolism in critically ill patients with AKI, and that intensive insulin therapy will result in substantial reductions in both whole-body and skeletal muscle protein breakdown thereby improving overall protein balance. We also hypothesize that this therapy will have favorable effects on the inflammatory and oxidative stress profile of patients with AKI. The metabolic response to these interventions will be assessed through stable isotope infusion techniques, allowing for the most precise assessment of protein and energy homeostasis.