SHORT-TERM STARVATION ALTERS THE FREE AMINO-ACID CONTENT OF THE HUMANINTESTINAL-MUCOSA

1. The effects of short-term starvation and refeeding on the free amin o acid concentrations of the intestinal mucosa were characterized in m ale subjects (n=6), using endoscopically obtained biopsy specimens fro m the duodenum and from all four segments of the colon. 2. The alterat ions in the amino acid concentrations in response to short-term starva tion were overall uniform in both duodenal and colonic mucosa as well as in plasma. Most amino acids decreased, whereas branched-chain amino acids increased. 3. In the colon, glutamic acid and glutamine decreas ed during the starvation period, whereas they remained unaltered in th e duodenum. This was the major difference in response to short-term st arvation between the amino acid concentrations in the intestinal mucos a of the duodenum and colon. 4. Refeeding for 3 days normalized the am ino acid concentrations except for glutamic acid, asparagine and histi dine, which remained low in the colon, and threonine, which showed an overshoot in both parts of the intestine. 5. The changes in mucosal am ino acid concentrations seen in response to starvation and refeeding w ere uniform in the four segments of the colon. This suggests that samp ling from the rectum/sigmoid colon will give representative values for the free amino acid concentrations of the entire large intestine.