The specificity and mechanism of altered intestinal transport of diabetic rats was studied with an everted ring technique. Increased intracellular accumulation of amino acids, as well as galactose and 3-O-methylglucose, was demonstrated in diabetes. The greater accumulation by diabetic intestine could not be attributed to a direct effect of the agent used to induce diabetes or to an alteration in food consumption. Although the changes were related to the severity of diabetes and could be reversed with treatment with insulin, they could not be modified by addition of insulin in vitro. The changes could not be induced in control intestine either with hyperglycemia from glucose infusion or preincubation with glucose in vitro. Although the higher concentration gradients of amino acids, galactose, and 3-O-methylglucose could result from increased energy utilization by diabetic intestine, an alteration of cell membrane function, as well, is suggested by the demonstration with kinetic studies of increased influx with an increase in V(max).

Amino Acids↗

PubMed1968

The role of sodium in intestinal glucose absorption in man.

The effect of luminal sodium on intestinal glucose absorption at a variety of glucose concentrations was studied with a segmental perfusion technique in normal subjects. Uphill glucose transport was inhibited with sodium-free perfusions with either mannitol or Tris-HCl as the osmotic replacement of sodium (P < 0.01-P < 0.001). This effect did not appear to be the result of solvent drag, as increasing net water absorption without supplying sodium to the lumen did not increase glucose absorption. Downhill glucose transport (infusion concentrations of 6.0-27.8 mmoles/liter), on the other hand, was not affected by the absence of sodium in the infusion solution. Glucose concentrations of upper intestinal fluid after normal carbohydrate meals were usually found to exceed serum concentrations; thus, downhill glucose absorption, with, at most, a very limited dependence upon intraluminal sodium concentration, may account for a significant part of normal carbohydrate absorption.

Adolescent↗

PubMedDate not supplied

Intestinal digestion and absorption of sucrose in experimental diabetes.

Intestinal sucrose hydrolysis and absorption of monosaccharide products was studied in vivo utilizing the segmental perfusion technique in diabetic and control rats. The proximal jejunum was perfused with 20 mM sucrose, 140 mM NaCl and 0.5% PEG with 14C-PEG, as the nonabsorbable marker. Rates of sucrose hydrolysis and adsorption of monosaccharide products (fructose, and glucose) were determined. There were no statistically significant differences between the diabetic and control rats. This indicates that the previously reported increase in sucrase activity in diabetes does not correlate with enhanced rates of sucrose hydrolysis. Several possibilities for the interpretation of these results are discussed.

Animals↗