EXCEPT FOR ALANINE, MUSCLE PROTEIN CATABOLISM IS NOT INFLUENCED BY ALTERATIONS IN GLUCOSE-METABOLISM DURING SEPSIS

Objective: To assess any relationship between hyperglycemia and muscle protein catabolism associated with critical illness. Design: Cohort a nalytic study. Setting: Clinical research center and intensive care un it of a university hospital. Participants: Six healthy volunteers and five patients with severe sepsis. Interventions: Study subjects were g iven infusions of 6,6,d(2) glucose and N-15 lysine for 6 hours. After infusion of the stable isotopes for 2 hours (basal period), dichloroac etate, which accelerates pyruvate oxidation, was given (dichloroacetat e period). Leg blood flow was measured by indocyanine green dye diluti on, and femoral artery and vein substrate concentrations were quantita ted.Main Outcome Measures: The metabolic rates of glucose production, oxidation, and clearance; the whole-body protein breakdown rate; and t he net efflux of amino acids from the leg were determined. Results: In comparison with the healthy volunteers, septic patients had significa nt elevations in glucose production, oxidation, and clearance, acceler ated protein catabolism, and greater net peripheral efflux of amino ac ids. Dichloroacetate significantly decreased glucose production and in creased the percentage of glucose directed toward oxidation in both he althy volunteers and septic patients. However, this dichloroacetate-in duced perturbation of glucose utilization had no significant effect on whole-body protein breakdown or the efflux of specific amino acids fr om the leg except for alanine, whose net efflux doubled (p less than o r equal to.05). Conclusions: The findings of this study demonstrate a universal acceleration in the metabolic rates of both intermediary glu cose metabolism and protein/amino acid catabolism during sepsis. Excep t for alanine, however, there appears to be no coupling between these two physiologic responses to sepsis.