title: Whole body leucine, phenylalanine, and tyrosine kinetics in end-stage liver disease before and after hepatic transplantation.
abstract: The kinetics of leucine, phenylalanine, and tyrosine metabolism following orthotopic human liver transplantation in end-stage liver disease in hospitalized patients were evaluated and compared to controls. The investigation was carried out by protein turnover studies using 13C leucine, D5-phenylalanine, and [U-14C] tyrosine by continuous infusion and employing a stochastic model in 32 patients with end-stage liver disease, 17 of whom went on to receive an hepatic allograft, and 7 controls without significant liver disease who underwent elective abdominal surgery. Mean tyrosine flux in the liver disease group was 3,242 +/- 811 (n = 32) v 2,899 +/- 688 mumol/h in controls (n = 7) (P less than .001), while the tyrosine oxidation was 328 +/- 179 v 422 +/- 185 mumol/h (P less than .001). Tyrosine clearance in pretransplant patients was 719 +/- 345 (n = 17) v 1,193 +/- 568 mL/min (P less than .005) in posttransplant patients (n = 17) with virtually no overlap. There was a significant correlation between serum albumin levels and the tyrosine clearance (r = .60, P less than .05), but correlations with other conventional liver function tests were of a low order. Leucine and phenylalanine kinetics in liver disease patients did not show any significant differences from controls. Leucine and tyrosine fluxes in controls did exhibit a significant correlation (r = .70, P less than .05), but no correlation was observed in patients with liver disease. These findings indicate that the kinetics of the amino acid tyrosine are substantially altered by end-stage liver disease, with the most profound effect on tyrosine clearance.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Laboratory of Nutrition and Infection, New England Deaconess Hospital, Boston, MA.
authors.forename: R L
authors.initials: RL
authors.lastname: Shanbhogue
authors.forename: B R
authors.initials: BR
authors.lastname: Bistrian
authors.forename: K
authors.initials: K
authors.lastname: Lakshman
authors.forename: L
authors.initials: L
authors.lastname: Crosby
authors.forename: S
authors.initials: S
authors.lastname: Swenson
authors.forename: D
authors.initials: D
authors.lastname: Wagner
authors.forename: R L
authors.initials: RL
authors.lastname: Jenkins
authors.forename: G L
authors.initials: GL
authors.lastname: Blackburn
mesh_terms: D002247:Carbon Isotopes; D005260:Female; D006801:Humans; D007700:Kinetics; D007930:Leucine / Q000378:metabolism*; D008107:Liver Diseases / Q000378:metabolism* / Q000601:surgery; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D010649:Phenylalanine / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D014443:Tyrosine; D010649:Phenylalanine; D007930:Leucine