title: Effect of two amino acid solutions on leucine turnover in preterm infants.
abstract: OBJECTIVE
  To assess the effect of two different parenteral amino acid mixtures, Trophamine and Primene, on leucine turnover in preterm infants.
  
  
  METHODS
  Leucine kinetics were measured with [5,5,5 D3]leucine tracer in 15 infants receiving Trophamine (group 'T') (mean birth weight 1,263 g) and 22 who received Primene (group 'P') (mean birth weight 1,336 g) during two study periods, within a few hours after birth but before introduction of parenteral amino acid solution, and again at postnatal day 7. The rate of appearance of leucine was calculated from the enrichment of alpha-ketoisocaproic acid in plasma.
  
  
  RESULTS
  There were no significant differences in leucine turnover within a few hours after birth in the two groups. In the infants who received Primene leucine turnover on day 7 was significantly lower than in those who received Trophamine (269 +/- 43 vs. 335 +/- 27, p < 0.05). Despite a higher intake of leucine in the Trophamine group (108 +/- 10 vs. 77 +/- 8 micromol.kg(-1).h(-1)), leucine released from proteins at day 7 was higher in this group compared to Primene (227 +/- 27 vs. 192 +/- 42 micromol.kg(-1).h(-1)).
  
  
  CONCLUSIONS
  Primene administration results in lower leucine released from proteins, an estimate of protein breakdown, than Trophamine in preterm infants. Increases in whole body leucine turnover in response to administration of i.v. amino acids is influenced by the composition of the amino acid mixture. The factors responsible for this difference remain to be elucidated.
authors.affiliation: Servicio de Neonatología, Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain. msaenz.hulp@salud.madrid.org
authors.forename: Miguel
authors.initials: M
authors.lastname: Sáenz de Pipaón
authors.forename: José
authors.initials: J
authors.lastname: Quero
authors.forename: Darcos J L
authors.initials: DJ
authors.lastname: Wattimena
authors.forename: Pieter J J
authors.initials: PJ
authors.lastname: Sauer
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage*; D004573:Electrolytes; D005947:Glucose; D006801:Humans; D007225:Infant Food; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000378:metabolism*; D007236:Infant, Small for Gestational Age / Q000097:blood / Q000378:metabolism; D007930:Leucine / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D010288:Parenteral Nutrition; D057947:Parenteral Nutrition Solutions; D012996:Solutions
chemical_list: D000596:Amino Acids; D004573:Electrolytes; D057947:Parenteral Nutrition Solutions; D012996:Solutions; C545824:amino-acid, glucose, and electrolyte solution; D007930:Leucine; D005947:Glucose