Degradation of Albumin by Isolated Segments of the Gastrointestinal Tract in Rats. ∗

Abstract

Summary

1. Studies of NaI¹³¹ absorption from and I¹³¹-albumin catabolism in isolated segments of gastrointestinal tract of rats are described. 2. One hour following the simultaneous injection of NaI¹³¹ into stomach, proximal, middle, and distal small intestinal segments, there was net gain of radioactivity in the gastric lumen, and a mean loss of 13.3 to 15.3% of the injected dose per cm2 of serosal surface in the small bowel segments. 3. After injection of 1.7-2.6 mg of I¹³¹-albu-min into stomach, proximal middle, and distal small bowel segments mean percentages catabolized per cm² in one hour in respective segments were 6.4, 10.2, 13.3, and 13.0. 4. Diversion of pancreatic and biliary secretions for 24 hours prior to study lowered these means to 4.0, 5.1, 2.9, and 4.9 respectively. 5. These studies indicate that the stomach and all levels of the small bowel possess significant potential for degrading serum albumin entering the lumen, and that pancreatico-biliary secretions make a significant, but not the only, contribution to this process.

The authors are grateful to Dr. Arthur Naitove, Dept. of Physiology, Dartmouth Med. School, for suggestions regarding surgical techniques used in this study.