title: Parenterally fed neonatal piglets have a low rate of endogenous arginine synthesis from circulating proline.
abstract: Parenterally fed neonatal piglets cannot synthesize sufficient arginine to maintain arginine status, presumably due to the intestinal atrophy that occurs with parenteral feeding. Parenteral feeding-induced atrophy can be reduced by the infusion of glucagon-like peptide 2 (GLP-2). GLP-2 infusion was hypothesized to increase the rate of endogenous arginine synthesis from proline, the major arginine precursor, in parenterally fed piglets receiving an arginine-deficient diet. Male piglets, fitted with jugular vein catheters for diet and isotope infusion, and femoral vein catheters for blood sampling (d 0), were allocated to a continuous infusion of either GLP-2 (n = 5; 10 nmol x kg(-1) x d(-1)) or saline (n = 5) for 7 d. Piglets received 2 d of a complete diet, followed by 5 d of an arginine-deficient [0.60 g x kg(-1) x d(-1)] diet. Piglets received primed, constant infusions of [guanido-(14)C]arginine to measure arginine flux (d 6) and [U-(14)C]proline (d 7) to measure proline conversion to arginine. Plasma arginine concentrations and arginine fluxes indicated a similar whole-body arginine status. Piglets receiving GLP-2 showed improvements in intestinal variables, including mucosal mass (P < 0.01) and villus height (P < 0.001), and a greater rate of arginine synthesis (micromol x kg(-1) x h(-1)) from proline (11.6 vs. 6.3) (P = 0.03). Mucosal mass (R(2) = 0.71; P = 0.002) and villus height were correlated (R(2) = 0.66; P = 0.004) with arginine synthesis. This study was the first to quantitate arginine synthesis in parenterally fed neonates and showed that although GLP-2 infusion increased arginine synthesis in a manner directly related to mucosal mass, this increased arginine synthesis was insufficient to improve whole-body arginine status in piglets receiving a low arginine diet.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
authors.forename: Kristine L
authors.initials: KL
authors.lastname: Urschel
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Evans
authors.forename: Craig W
authors.initials: CW
authors.lastname: Wilkinson
authors.forename: Paul B
authors.initials: PB
authors.lastname: Pencharz
authors.forename: Ronald O
authors.initials: RO
authors.lastname: Ball
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000831:Animals, Newborn; D001120:Arginine / Q000096:biosynthesis* / Q000172:deficiency; D001284:Atrophy; D053767:Glucagon-Like Peptide 2 / Q000008:administration & dosage; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology; D008297:Male; D010288:Parenteral Nutrition / Q000009:adverse effects / Q000662:veterinary; D011392:Proline / Q000097:blood*; D034421:Sus scrofa / Q000378:metabolism*
chemical_list: D053767:Glucagon-Like Peptide 2; D001120:Arginine; D011392:Proline