Small-intestinal transit during total parenteral nutrition in the rat

This investigation was designed to test the hypothesis that alterations in small-bowel motility are associated with total parenteral nutrition (TPN). Motility, as reflected by intestinal transit, was studied in rats maintained by TPN for 7–10 days and compared to that of rats fed an oral diet isocaloric with the intravenously administered solution. Transit was measured by injecting radioactively labeled chromium (Na₂ ⁵¹CrO₄) into the duodenum via permanently implanted catheters. Fifteen minutes after injection of the label, animals were killed and the linear distribution of the isotope in the gut was determined. The leading edge of radioactivity traversed 75–87% (95% confidence limit) of the gut length in enterally fed rats and 83–97% in rats on TPN. The difference between the average position of these fronts for the two groups was not statistically significant (P>0.05). In addition, the regression of percent radioactivity traversing or present in a given segment on gut length yielded a slope with 95% confidence limits of –10.48 to –15.02 for orally fed control rats and –9.83 to –12.87 for rats on TPN. Differences between these slopes were not statistically significant (P>0.05). Results support the conclusion that factors which regulate small-bowel motility are not altered significantly by TPN during the time that other functional and structural changes reportedly occur.This study was supported by NIH Grants AM 18164, AI 11361, AM 16305. Dr. Castro is the recipient of NIH Research Career Development Award AI 00087. Dr. Weisbrodt is the recipient of PHS Research Scientist Development Award DA 00022.