title: Leucine metabolism at graded amino acid intakes in children receiving parenteral nutrition.
abstract: To assess the response of protein turnover to graded levels of amino acid (AA) intakes, leucine kinetics were determined in six 8- to 16-yr-old patients in a stable nutritional status receiving home parenteral nutrition (PN) for short-bowel syndrome or intestinal pseudo-obstruction syndrome. Although daily energy intake was kept constant at 68.7 +/- 13 kcal/kg lean body mass (LBM) with 25.4 +/- 3.6% lipid, patients were given, for three consecutive 7-day periods, 0.7, 1.5, or 2.5 g AA.kg LBM-1.day-1, with the order of the regimens being randomized. On day 7 of each period, a 4-h infusion of L-[1-13C]leucine was performed during intravenous feeding; plasma [13C]ketoisocaproate and expired 13CO2 enrichments were used to assess whole body leucine turnover (Ra), oxidation rate (Ox), nonoxidative disposal [an estimate of protein synthesis (S)], and leucine derived from protein breakdown (B). Urine collection (24 h) was performed for determination of nitrogen excretion. Results indicate a dose-dependent rise in plasma leucine concentration, Ra, and Ox but no significant change in B. There was a significant increase of S (P = 0.04 analysis of variance) with increased AA intakes as well as net leucine balance (P = 0.02). Results are consistent with improved leucine balance, when leucine intake increases, despite increased leucine oxidation. The net protein gain observed with higher AA intakes may suggest a beneficial effect for children receiving long-term PN.
authors.affiliation: Service de Gastroentłerologie et Nutrition, Hôpital des Enfants Malades, Institute National de la Santé et de la Recherche Médicale Unité 290, Paris, France.
authors.forename: O
authors.initials: O
authors.lastname: Goulet
authors.forename: S
authors.initials: S
authors.lastname: DePotter
authors.forename: J
authors.initials: J
authors.lastname: Salas
authors.forename: J J
authors.initials: JJ
authors.lastname: Robert
authors.forename: M
authors.initials: M
authors.lastname: Rongier
authors.forename: M
authors.initials: M
authors.lastname: Ben Hariz
authors.forename: J
authors.initials: J
authors.lastname: Koziet
authors.forename: J F
authors.initials: JF
authors.lastname: Desjeux
authors.forename: C
authors.initials: C
authors.lastname: Ricour
authors.forename: D
authors.initials: D
authors.lastname: Darmaun
mesh_terms: D000293:Adolescent; D000596:Amino Acids / Q000008:administration & dosage* / Q000494:pharmacology; D002245:Carbon Dioxide; D002648:Child; D005260:Female; D006801:Humans; D007418:Intestinal Pseudo-Obstruction / Q000378:metabolism / Q000628:therapy; D007651:Keto Acids / Q000097:blood; D007930:Leucine / Q000097:blood / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010288:Parenteral Nutrition; D012119:Respiration; D012778:Short Bowel Syndrome / Q000378:metabolism / Q000628:therapy
chemical_list: D000596:Amino Acids; D007651:Keto Acids; D002245:Carbon Dioxide; C013082:alpha-ketoisocaproic acid; D007930:Leucine