Maturational patterns of carbohydrases in the ileal remnant of rats after jejunectomy at infancy.

The enteric epithelium of suckling rat undergoes dramatic functional and cytokinetic changes (redifferentiation) with maturation. Ileal epithelial maturation was studied in infant rats subjected to 60% proximal enterectomy at age 10 d in an effort to examine redifferentiation mechanisms. Two months after resection the residual ileal remnant was increased in diameter, weight, total protein, and DNA per unit length compared with ileal segments from control littermates that had laparotomy without resection. The residual ileum demonstrated increased sucrase activity per unit length but was indistinguishable from control ileal segments in activity per unit DNA or villus distribution. Lactase activity was negligible in all segments of the residual intestine. Villus height and crypt depth were increased in the residual ileum with slight increases in cell turnover and cell-migration rates. These results show the presence of an intrinsic program for regulation of ileal epithelial maturation and its resistance to alteration by a major stimulus applied before its expression.