ROLE OF ORAL INTAKE ON INTESTINAL ADAPTATION AFTER SMALL BOWEL RESECTION IN GROWING RATS

Fifty percent resection of the proximal small intestine was performed on growing male Sprague-Dawley rats which were then fed either orally (po) or intravenously (iv), with a liquid elemental diet. After 8 days, gut and mucosal weight, DNA, protein, sucrase, enterokinase, and alanine uptake were measured in the small intestine divided into three segments. Rates of weight gain were similar in the two groups (Fig. 1). Gut and mucosal weights (Fig. 2) and mucosal protein, DNA, and sucrase per cm intestine (Figs. 3 and 4) were all higher (P < 0.01) in the po group in all segments of the small intestine. However, protein, DNA, and sucrase per g mucosa were not different in the two groups. In contrast, the specific transport activity (distribution ratio) of alanine was increased (P < 0.01) in the iv group whereas uptake per cm was similar (Fig. 5). These results emphasize the importance of oral nutrition to the adaptation of the remaining gut in growing rats after proximal resection. On the other hand, the increased specific transport activity in parenteral feeding indicates that absorptive function at the cellular level may be independent of oral intake. Speculation: After intestinal resection, parenteral nutrition should be supplemented with an elemental oral diet as soon as possible in order to optimize adaptation. Gastrointestinal hormones released by food or dependence on luminal sustenance may play an important role in the adaptive process. © 1978 International Pediatric Research Foundation, Inc.