Glucose transport by brush‐border membrane vesicles after proximal resection or ileo‐jejunal transposition in the rat.

Abstract

SUMMARY1. The functional properties of the ileal mucosa following jejunal resection or interposition in the jejunum were studied with the help of membrane vesicles.2. Despite the development of functional and morphological features in the mucosa which are more generally associated with the jejunum than with the ileum, examination of brush-border vesicles derived from ileal and jejunal enterocytes from resected or transposed intestines reveals that the functional characteristics of apical membranes isolated from the different regions of the intestine are maintained after these surgical manoeuvres. Vesicles from control ileum develop an 'overshoot' uptake of glucose that is 3-4 times smaller than that of jejunal vesicles, a difference that is still observed in membranes prepared from mucosa of ileal loops following proximal resection or interposition in the jejunum.

GALACTOSE TRANSPORT ACROSS RAT SMALL INTESTINE IN VIVO FOLLOWING DISTAL RESECTIONS OF VARYING EXTENTS

“…Glucose transport into isolated brush border membrane vesicles is unaltered by intestinal resection (Menge, Murer & Robinson, 1978). Recent studies (Urban & Michel, 1983) have demonstrated that morphological growth preceded and did not parallel functional adaptation.…”

Patterns, Mechanisms and Signals for Intestinal Adaptation

“…67], but the life span of the cells may be unchanged [68] or shortened [69], If this decreased life span can be inter preted in terms of a diminished maturation of the enterocytes, the results [70] of a de creased microvillus surface area in the villus compartment may be the morphological re flection of an immature cell state. Quantita tive histochemical data [71] point in the same direction: after proximal resection, en zyme activities of two disaccharidases did not change at the base of the villi, whereas in the case of a-glucosidase the Vmax values were reduced at the transition zone between the middle and apical third of the villi in the hypoplastic mucosa, while other enzyme ac tivities remain unchanged. In spite of the unchanged absorptive capacity of the indi vidual enterocytes in the hyperplastic mu cosa which has been demonstrated by auto radiographic studies, [26], and by the inves tigations on BBM vesicles.…”

Adaptation of Epithelial Ion Transport in the Short Bowel Syndrome

“…Menge et al [10] found no increase in glucose uptake into brush border membrane vesicles 1 month after surgery and Weser and Hernandes [12], who measured glucose uptake into isolated cells, also did not find an increase under the conditions of the short bowel syndrome 5-6 weeks after sur gery. Two reasons may be responsible for this discrepancy to our present findings.…”