Abstract
Studies in congenital glucose-galactose malabsorption (GGM) have indicated an abnormality in small intestinal glucose and galactose transport but the precise site of the defect has not been defined. We have therefore investigated Na+-coupled D-glucose uptake, and Na+/H+ exchange in a patient with GGM using brush border membrane vesicles (BBMV) prepared from jejunal biopsies using a miniaturised Mg++-precipitation technique. The diagnosis was confirmed by clinical presentation, response to diet and jejunal perfusion studies, which showed markedly defective glucose and galactose absorption (p < 0.001) and normal fructose transport.
In contrast to control BBMV, in which an inwardly directed Na+-gradient (100mmol/l) enhanced 15 sec D-glucose uptake × 5.5 (p < 0.02), glucose uptake by BBMV from the patient showed no such enhancement with Na+ (p < 0.0025). Na+/H+ exchange was intact, with a 6-fold enhancement of Na+ uptake by an outwardly directed H+ gradient (pH in: 6.0; out: 7,4) at 15 sec.
These studies therefore confirm for the first time, that a defect in brush border Na+-coupled glucose uptake is present in GGM, and suggest that BBMV studies may be the optimal technique for confirmation of the diagnosis.
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Booth, I., Patel, P., Sule, D. et al. 16. DEMONSTRATTCN OF DEFECTIVE JEJUNAL BRUSH BORDER Na+-COUPLED GLUCOSE TRANSPORT IN CONGENITAL GLUCOSE-GALACTCSE MALABSORPTION. Pediatr Res 22, 98 (1987). https://doi.org/10.1203/00006450-198707000-00037
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DOI: https://doi.org/10.1203/00006450-198707000-00037