Abstract

Distilled water, a carbohydrate-electrolyte (CE; 4% sucrose, 2% glucose, 17.2 meq/l NaCl, and 2.8 meq/l KCl) solution, or a 10% glucose solution, all containing the nonabsorbed indicator polyethylene glycol (PEG) and deuterium oxide (D₂O, 30 ppm), were infused (15 ml/min) into the duodenojejunum of seven men by using the triple lumen technique. Net water absorption was determined directly from the change in PEG concentration and was calculated from plasma D₂O derived from D₂O in the perfusion solutions. The protocol included a 45-min equilibration period followed by a 90-min test period. Intestinal samples were drawn at 10-min intervals from 15 to 45 min and at 15-min intervals thereafter. Blood was drawn at 45, 50, 55, 60, 75, 90, 105, 120, and 135 min.Intestinal samples were analyzed for D2O, Na+, K+, osmolality, PEG, and glucose; blood was analyzed for D2O. Results (+/- SE; positive values secretion, negative values absorption) showed net fluid absorption from distilledwater (-9.40 +/- 1.28 ml.h-1.cm-1) and the CE (-13.30 +/- 1.22 ml.h-1.cm-1) solution, but net secretion (4.40 +/- 1.25 ml.h-1.cm-1) from the 10% glucose solution. All values were significantly (P less than 0.05) different from each other. Perfusing the CE solution caused net Na+ and K+ absorption, whereas perfusing the 10% dextrose solution caused net electrolyte secretion. Rates of D₂O accumulation in the plasma were independent of the solutions perfused.(ABSTRACT TRUNCATED AT 250 WORDS)