Role of the small bowel in regulating food intake in rats.

This study tested the hypothesis that exposure of the lower intestine to nutrients decreases subsequent food intake. Eight male Sprague-Dawley rats underwent jejunoileal bypass surgery with 8 cm of proximal jejunum anastomosed to 5 cm of terminal ileum in an end-to-side fashion. Eight control rats had sham bypass surgery with similar intestinal incisions that were reanastomosed in normal continuity. Another group of eight rats underwent ileal transposition (IT). A 10-cm segment of terminal ileum was transected, leaving the mesentery and blood supply intact, and transposed to the jejunum 8 cm from the ligament of Treitz. Thus total intestinal length was intact. Eight control rats had similar intestinal transections reanastomosed in normal continuity. A similar pattern of decreased food intake in the first 1-2 wk occurred in both bypass and IT rats. The values were significantly different from the respective sham surgery control groups. Body weights decreased, but the fall was greater in bypass rats. These data suggest that partially digested food in the lower intestine decreases food intake.