Effect of protein ingestion on splanchnic and leg metabolism in normal man and in patients with diabetes mellitus.

Abstract

A C T The inter-organ flux of substrates after a protein-rich meal was studied in seven healthy subjects and in eight patients with diabetes mellitus.Ar- terial concentrations as well as leg and splanchnic ex- change of amino acids, carbohydate substrates, free fatty acids (FFA), and ketone bodies were examined in the basal state and for 3 h after the ingestion of lean beef (3 g/kg body wt).Insulin was withheld for 24 h before the study in the diabetic patients.In the normal subjects, after protein ingestion, there was a large amino acid release from the splanchnic bed predominantly involving the branched chain amino acids.Valine, isoleucine, and leucine accounted together for more than half of total splanchnic amino acid out- put.Large increments were seen in the arterial concen- trations of the branched chain amino acids (100-200%) and to a smaller extent for other amino acids.Leg ex- change of most amino acids reverted from a basal net output to a net uptake after protein feeding which was most marked for the branched chain amino acids.The latter accounted for more than half of total peripheral amino acid uptake.Alanine and glutamine were con- tinuously taken up by the splanchnic tissues and re- leased by the leg tissues after the protein meal, although This work was presented in part at the 67th Annual Meeting of the American Society for Clinical Investigation, Atlantic City, N.