Intestinal transit in dogs is accelerated by volume distension during fat-induced jejunal brake.

Intestinal transit is accelerated by volume distension and slowed by nutrient load. We hypothesized that the accelerating effect of volume distension might overcome the slowing effect of nutrient. To test this hypothesis, we compared intestinal transit in five dogs equipped with duodenal and mid-intestinal fistulas. The proximal half of the small intestine was perfused with 60 mM oleate, while the distal half of the small intestine was either perfused with buffer (with distension) or left unperfused (without distension). We found that intestinal transit was slowed by oleate (with marker recovery reduced from 85.8 +/- 5.3 to 39.4 +/- 7.5%) (P < 0.01) and that volume distension accelerated intestinal transit so that marker recovery increased from 39.4 +/- 7.5 without distension to 60.8 +/- 6.3% with distension (P < 0.05). We concluded that intestinal transit is accelerated by volume distension during fat-induced jejunal brake.