[Amino acid metabolism in diabetes mellitus].

A B ST R A CT Splanchnic and leg exchange of glucose, lactate, pyruvate, and individual plasma amino acids was studied in diabetics 24 hr after withdrawal of insulin and in healthy controls. Measurements were made in the basal postabsorptive state and during the administration of glucose at a rate of 2 mg/kg per min for 45 min. In the basal state, net splanchnic glucose production did not differ significantly between diabetics and controls. However, splanchnic uptake of alanine and other glycogenic amino acids was 11-2 times greater in the diabetics, while lactate and pyruvate uptake was increased by 65-115%. Splanchnic uptake of these glucose precursors could account for 32% of hepatic glucose output in the diabetics, as compared to 20% in the controls. This increase in precursor uptake was a consequence of a twoto threefold increment in fractional extraction of these substrates inasmuch as arterial levels of alanine, glycine, and threonine were reduced in the diabetics, while the levels of the remaining substrates were similar in the two groups. Peripheral output of alanine and other glycogenic amino acids as reflected in arterio-femoral venous differences was similar in both groups. An elevation in arterial valine, leucine, and isoleucine was observed in the diabetics, but could not be accounted for on the basis of altera-