Fig. 2.

TPN-derived leucine accumulates in the small bowel and is incorporated into luminal bacteria. ¹³C mass isotopomer flux analysis of small bowel effluent (A), serum (B), bile (D), and small bowel intraluminal bacterial biomass (E) from fed and TPN-dependent mice. C: ratio of [¹³C]-leucine concentration in small bowel effluent to serum in fed and TPN-dependent mice. Intravenous infusions were supplemented with [¹³C]leucine for the entire 6 days of treatment or for the final 2 days only. Bile and bacteria samples were pooled prior to analysis. *P < 0.05, **P < 0.01.