EFFECT OF TOTAL PARENTERAL ALIMENTATION (TPA) ON RAT SMALL INTESTINE

Abstract

Rats were killed on day 0 and after 3, 7, 10 and 14 days of TPA, isocaloric rat chow feedings(IC), or starvation. In each group the small intestine was removed for determination of its total weight(TW), mucosal weight(MW), mucosal protein(MP), mucosal DNA, and mucosal glycolytic enzyme activities. Both TPA and IC rats were in positive N balance; weight gains were 5 and 3.5gm/d, respectively. Starved rats lost 10 gm/d. In IC rats, none of the variables changed significantly over 14 days. In TPA rats, both TW and MW decreased by 40% within 3 days, after which no further changes occurred. Both mucosal protein and DNA of TPA rats were 40% lower by 3 days and remained at this level. TW and MW of starved rats decreased by 63% over 10 days, while both mucosal protein and DNA decreased 65%. In contrast to the changes during TPA, all variables fell continuously, during starvation. Mucosal Protein: DNA ratios remained constant in all groups, suggesting a decrease in the total number of cells. Specific activities of pyruvate kinase and both fructose-1-phosphate and fructose-1,6-diphosphate aldolases remained constant in all 3 groups, but because of decreased mucosal protein and DNA contents, total intestinal activity of all enzymes was significantly decreased. These findings show that although increases in body weight can be achieved with TPA, it does not adequately maintain intestinal cell mass.