Fed state protein metabolism in diabetes mellitus

Current knowledge concerning the physiologic regulation of protein anabolism during feeding is both limited and debated; little information is available on the effects of pathological conditions such as diabetes mellitus. This is due largely to methodological problems and the technical difficulties associated with the isotope dilution techniques used to estimate protein kinetics in the fed state. Data that are available suggest that meal intake induces protein anabolism in healthy subjects by reducing endogenous proteolysis and selectively stimulating protein synthesis, with amino acids and insulin playing the major regulatory role. Data obtained in subjects with noninsulin-dependent diabetes mellitus demonstrate that the impaired insulin action on glucose metabolism characteristic of that disease may not be associated with abnormal protein metabolism in the fed state. Severe insulin deficiency, as occurs in insulin-dependent diabetes, adversely affects nitrogen balance; at present, however, the effects of poor postprandial glycemic control on protein kinetics in subjects with insulin-dependent diabetes remain to be established.