Effect of perfusion of a jejunal blind loop on intestinal thymidine uptake in the rat

The effect of perfusing a jejunal loop with saline or glucose solution on the thymidine uptake by the intestinal cells was studied in rats. Two weeks after the construction of the loop, it was perfused for 24 h with glucose or saline of either 280 or 450 mOsm/kg. A control group received no perfusion. The weight per unit length, the DNA concentration, and the DNA-specific activity of 3H-labeled thymidine was recorded in the duodenum, the loop, the remaining small intestine and the colon. The thymidine uptake in the perfused loop relative to the unperfused parts of the small intestine was higher in the groups that received glucose or hypertonic saline than in the groups that received isotonic saline and the control group. In the colon, the uptake relative to the uptake in the unperfused small-intestinal segments was reduced in all the perfused groups compared with the controls. The tissue DNA concentration and the weight per unit length of the intestinal segments were not changed by the perfusions. The results are discussed in relation to current hypotheses on the regulation of intestinal cell proliferation.