title: Association of tyrosine with insulin resistance in hepatitis C virus-related chronic liver disease.
abstract: OBJECTIVE
  Insulin resistance (IR) increases during the early stages of hepatitis C virus (HCV)-related chronic liver disease and is a sign of poor prognosis as well as a risk factor for hepatic fibrosis and hepatocellular carcinoma. We aimed to determine the factors affecting IR in HCV-related chronic liver disease.
  
  
  METHODS
  We retrospectively examined 71 patients with HCV-related chronic liver disease and analyzed various parameters, including amino acids, as possible predictors of IR. IR was assessed using the Homeostasis Model of Assessment - Insulin Resistance (HOMA-IR). Amino acids were assayed by examining branched-chain amino acids (BCAA), tyrosine level, and the ratio of BCAA to tyrosine level (BTR).
  
  
  RESULTS
  HOMA-IR was significantly correlated with body mass index, platelet count, prothrombin time, hemoglobin, total bilirubin, total protein, albumin, total cholesterol, fasting glucose, BTR (r = -0.46, P = 0.0001) and tyrosine (r = 0.55, P < 0.0001). However, BCAA were not significantly correlated with HOMA-IR (r = -0.21, P = 0.082). In multivariate analysis, only two factors were identified as independent parameters contributing to a HOMA-IR of 2.5 or more: total cholesterol (odds ratio [OR], 6.511; 95% confidence interval [95% CI], 1.554-27.284; P = 0.010) and tyrosine (OR, 4.839; 95% CI, 1.087-21.549; P = 0.039).
  
  
  CONCLUSIONS
  Serum tyrosine levels may be associated with IR in patients with HCV-related chronic liver disease.
authors.affiliation: Departments of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Oono
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamasaki
authors.forename: Junichi
authors.initials: J
authors.lastname: Zaitsu
authors.forename: Issei
authors.initials: I
authors.lastname: Saeki
authors.forename: Takuya
authors.initials: T
authors.lastname: Iwamoto
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Harima
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Marumoto
authors.forename: Isao
authors.initials: I
authors.lastname: Hidaka
authors.forename: Yohei
authors.initials: Y
authors.lastname: Urata
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Taro
authors.initials: T
authors.lastname: Takami
authors.forename: Makoto
authors.initials: M
authors.lastname: Segawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Uchida
authors.forename: Shuji
authors.initials: S
authors.lastname: Terai
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kunitugu
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tanabe
authors.forename: Isao
authors.initials: I
authors.lastname: Sakaida
keywords: chronic hepatitis; hepatic fibrosis; hepatitis C virus; insulin resistance; liver cirrhosis; tyrosine