JEJUNAL FUNCTION AND PLASMA AMINO-ACID-CONCENTRATIONS IN THE SEGMENTAL TRISOMIC TS65DN MOUSE

Mice trisomic for the distal portion of MMU 16 (Ts65Dn) were examined for differences in jejunal function and plasma amino acids as compared to diploid controls. Eighteen control and 19 Ts65Dn mice were compare d for whole-body and intestinal O-2 consumption, jejunal glucose uptak e, and plasma amino acid concentrations. Ts65Dn mice consumed less (P < 0.02) O-2 per gram of fasted body weight. No significant differences were found in either active or passive glucose uptake. Oxygen consump tion by jejunal tissue was not different between Ts65Dn and control mi ce. The apparent energetic efficiency of jejunal active glucose uptake (eta mol ATP expended/eta mol glucose uptake) was significantly highe r (115.6 vs. 80.8; P < 0.05) in Ts65Dn mice. Histomorphometric analysi s of jejunal mucosa showed that Ts65Dn mice had shorter villus height (P < 0.04) and decreased planar villus circumference (P = 0.05). No di fferences were found in total jejunal protein (mu g/g) or DNA (mg/g) c oncentrations. Significantly higher concentrations of plasma tyrosine, phenylalanine, valine, leucine, isoleucine, and citrulline (P < 0.05) were found in Ts65Dn mice. Lower plasma concentrations of hydroxyprol ine were detected in Ts65Dn mice (P < 0.05). These data suggest that T s65Dn mice have anomalies in digestive function and amino acid metabol ism as compared to normal, diploid controls.