Structural and functional correlations in the hypertrophic mucosa of intestinal remnants following resection in rats

Microdissection techniques were applied to determine the absolute increase in villus size and absorptive surface in the mucosa of rat intestinal remnants 3 weeks after 60% proximal resection. Adjacent tissues were used to evaluate the operational kinetic parameters describing the influx of L-phenylalanine and alpha-methyl-D-glucoside into intestinal rings. The villi of ileal remnants were enlarged significantly in all dimensions; the mean surface area of the villus was 2.5 times, and mucosal:serosal surface ratio 1.9 times larger than normal. The influx of phenylalanine and alpha-methyl-glucoside into the mucosa of ileal remnants was reduced, but the change could not be ascribed to an attenuation of one specific kinetic parameter. Using the microdissection data to transform the Vmax-values to a mucosal area basis, we could demonstrate that the Vmax for both substrates was smaller than normal. The results may derive from changes in the maturity of the cell population in intestinal remnants.