title: The association of plasma free amino acids with liver enzymes in Type 2 diabetic patients.
abstract: BACKGROUND
  Elevated γ-glutamyl transpeptidase (GGT) and alanine aminotransferase (ALT) could predict the risk of Type 2 diabetes (T2D), but the reason for their elevation was unclear. GGT and ALT mediated the metabolism of many amino acids (AA). Up to now, it was not investigated whether abnormal AA concentration was associated with elevated liver enzymes.
  
  
  OBJECTIVE
  This study was to investigate the status of AA in T2D and their relationship with liver enzymes.
  
  
  METHODS
  A total of 132 T2D patients and 137 healthy controls were recruited. Plasma free AA were measured by high-performance liquid chromatography. The contribution of individual AA to liver enzymes was assessed by stepwise linear regression.
  
  
  RESULTS
  a) The levels of alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, methionine, glutamate, and lysine were higher while the level of glycine was lower in T2D than in controls (all p<0.01). b) Glutamate contributed to GGT in T2D, and its contribution was even greater than that of waist circumference. Leucine, lysine, and glutamate contributed to ALT.
  
  
  CONCLUSIONS
  There were significant differences in plasma AA profile between T2D and controls. Abnormal AA might contribute to elevated liver enzymes. The interaction between AA, liver enzymes, and the risk of T2D should be further investigated by prospective studies.
authors.affiliation: Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu, PR China.
authors.forename: T
authors.initials: T
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Long
authors.forename: H
authors.initials: H
authors.lastname: Yu
authors.forename: X
authors.initials: X
authors.lastname: Ran
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.forename: H
authors.initials: H
authors.lastname: Lu
authors.forename: X
authors.initials: X
authors.lastname: Xie
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Ren
authors.forename: J
authors.initials: J
authors.lastname: Shi
authors.forename: H
authors.initials: H
authors.lastname: Tian
mesh_terms: D000410:Alanine Transaminase / Q000097:blood*; D000596:Amino Acids / Q000097:blood*; D015992:Body Mass Index; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000201:enzymology; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008099:Liver / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D000596:Amino Acids; D005723:gamma-Glutamyltransferase; D000410:Alanine Transaminase