Blood amino acid compartmentation in obese rats is specifically altered in the iliac vein.

Amino acid concentration in blood cells and plasma and the calculated blood cell to plasma gradients (C/P) were measured in different blood vessels (aortic artery and portal, hepatic, iliac and renal veins) from both control and cafeteria diet obese rats. Essential amino acids are increased in plasma in all blood vessels in obese rats. The iliac vein was the only vessel in which cell concentration of amino acids, and mainly the mean of the combined non-essential amino acids, was affected by obesity. Only in the iliac vein were C/P values of the combined amino acids, including both essential and non-essential, significantly lower in obese versus control rats. These results also show that there are differences between sampling sites which should be noted in the design of physiological studies of amino acid metabolism.