ARS | Publication request: Kinetics of splanchnic 13C-cysteine metabolism in infant pigs

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2006
Publication Date: May 1, 2006
Repository URL: http://www.faseb.org
Citation: Cottrell, J., Stoll, B., Burrin, D. 2006. Kinetics of splanchnic 13C-cysteine metabolism in infant pigs [abstract]. Journal of Federation of American Societies for Experimental Biology. 20(4):A9.

Technical Abstract: Cysteine is a conditionally essential amino acid in neonates that can be synthesized from methionine by transsulfuration. We previously showed that methionine transsulfuration occurs in the GI tract of young pigs. Cysteine use by the gut epithelial cells may be important for maintenance of glutathione synthesis and cellular redox function. Our aim was to quantify the extent of gastrointestinal first-pass cysteine metabolism in young pigs. Four-week-old, formula fed piglets (n=10) were given an intragastric (IG) and intravenous (IV) [1-13C]-cysteine infusion (IR = 15 micro-mol x kg x -1 x h x-1) on two separate days in a cross-over design. Arterial isotopic enrichments of cysteine and CO2were measured by GC/IR-MS and whole body fluxes are expressed as micro-mol x kg x -1h x -1. Whole body cysteine flux (WB) was higher (P<0.01) during the IG than IV infusion (267 vs 154). Fractional (%IR) 13-Cys oxidation was similar during IG vs IV infusion (38.5 vs 36.2%). First-pass fractional splanchnic extraction was 39 +/- 7% of enteral 13-Cys intake, of which 17% was oxidized to 13O2. The mean dietary Cys absorption during both infusion modes was similar, representing 80% of dietary intake, indicating that gut utilization was 20% of intake. We conclude that despite the higher whole body flux with enteral versus IV infusion, the fractional 13-Cys oxidation is similar. Gut utilization consumes 20% of the dietary Cys intake and represents half of first-pass splanchnic use.