FUNCTIONAL AND STRUCTURAL CHARACTERISTICS OF RAT INTESTINAL-MUCOSA FOLLOWING ILLEO-JEJUNAL TRANSPOSITION

  • 1 January 1978
    • journal article
    • research article
    • Vol. 25  (2) , 150-154
Abstract
The transformation of the rat ileal mucosa following interposition into the jejunum was examined with respect to its functional and structural characteristics. Morphometric studies show that there is an increase in the size of the villi and crypts in the same proportions, such that the structures become longer than those of normal jejunal mucosa. There is no change in villus width or epithelial cell height and no evidence of mucosal damage. In agreement with these observations, there is an increase in the amount of DNA/unit weight mucosa in the transposed ileum. L-phenylalanine accumulation in vitro by transposed loops is reduced to the level of the control jejunum, whereas .beta.-methyl-D-glucose uptake is unchanged. Biochemical and histochemical determinations of various enzyme activities reveal that the levels in the transposed mucosa are much lower than in the controls. Although certain features of the transposed ileum resemble those of the normal jejunum, this does not apply to all characteristics. The ileal mucosa possibly retains its normal functional properties, but undergoes hyperplastic changes, possibly as a result of contact with chyme that is richer in nutritive material, resulting in the establishment of a more immature cell population with a global reduction in enzyme levels and transport capacities.