Intestinal water absorption from select carbohydrate solutions in humans.
Eight men positioned a triple-lumen tube in the duodenojejunum. By use of segmental perfusion, 2, 4, 6, or 8% solutions of glucose (111-444 mM), sucrose (55-233 mM), a maltodextrin [17-67 mM, avg. chain length = 7 glucose units (7G)], or a corn syrup solid [40-160 mM, avg. chain length = 3 glucose units (3G)] were perfused at 15 ml/min for 70 min after a 30-min equilibration period. All solutions were made isotonic with NaCl, except 6 and 8% glucose solutions, which were hypertonic. An isotonic NaCl solution was perfused as control. Water absorption (range: 9-15 ml.h-1.cm-1) did not differ for the 2, 4, and 6% CHO solutions but was greater (P < 0.05) than absorption from control (3.0 +/- 2.2 ml.h-1.cm-1). The 8% glucose and 3G solutions reduced (P < 0.05) net water flux compared with their 2, 4, and 6% solutions, but 8% sucrose and 8% 7G solutions promoted water absorption equivalent to lower CHO concentrations. Water absorption was independent of [Na+] in the original solution. In the test segment, 1) Na+ flux correlated with net water flux (r = 0.72, P < 0.01), K+ (r = 0.78, P < 0.01), and [Na+] (r = 0.68, P < 0.001); 2) Na+ absorption occurred at luminal [Na+] as low as 50 mM; 3) glucose transport increased linearly over the luminal concentration range of 40-180 mM; and 4) net water flux was similar over a range of glucose-to-Na+ concentration ratios of 0.4:1 to 3.5:1.(ABSTRACT TRUNCATED AT 250 WORDS)
Gisolfi
C V
CV
Department of Exercise Science, University of Iowa College of Liberal Arts, Iowa City.
Summers
R W
RW
Schedl
H P
HP
Bleiler
T L
TL
D000328:Adult; D050260:Carbohydrate Metabolism; D004386:Duodenum / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology*; D008297:Male; D009391:Nephelometry and Turbidimetry; D009994:Osmolar Concentration; D011134:Polysaccharides / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012996:Solutions; D013395:Sucrose / Q000378:metabolism; D014867:Water / Q000378:metabolism*
D011134:Polysaccharides; D012996:Solutions; D014867:Water; D013395:Sucrose; C008315:maltodextrin; D012964:Sodium; D005947:Glucose; D011188:Potassium