title: Gender differences in plasma growth arrest-specific protein 6 levels in adult subjects.
abstract: BACKGROUND
  Growth-arrest-specific 6 (Gas6) is recognized as a secreted vitamin K-dependent protein, as it interacts with receptor tyrosine kinases of the TAM (Tyro-3, Axl, Mer) family. The plasma Gas6 are important to the inflammatory process, and are involved in diverse human diseases. Few studies have shown plasma Gas6 concentration varies with genders. We determined whether plasma Gas6 concentrations are associated with sex hormones in both genders.
  
  
  METHODS
  A total of 589 adult subjects, including 361 male and 228 female were recruited. Plasma Gas6 concentration, biochemical, testosterone, estradiol (E2), and sex hormone-binding globulin were assayed. The indices of free androgen (FAI) and free E2 (FEI) were calculated.
  
  
  RESULTS
  Significantly higher Gas6 concentrations were observed in adult male rather than female (P<0.05). In univariate regression analysis, plasma Gas6 concentrations were positively associated with FAI in male (β=0.167, P=0.002) and both E2 and FEI in female (β=0.384, P<0.001 andβ=0.292, P<0.001, respectively). Otherwise, Gas6 concentrations were inversely associated with ages in both genders (β=-0.234, P<0.001 in male and β=-0.226, P=0.001 in female, respectively). In multivariate regression analysis, only age in male and E2 in female were independent variables to determine the plasma Gas6 concentrations (β=-0.231, P=0.002 and β=0.458, P=0.001).
  
  
  CONCLUSIONS
  Plasma Gas6 is associated with sex hormones in female and ages in male, indicating a potential role of sex hormones and ages involving the Gas6/TAM system.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Yi-Jen
authors.initials: YJ
authors.lastname: Hung
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chien-Hsing
authors.initials: CH
authors.lastname: Lee
authors.affiliation: School of Dentistry, National Defense Medical Center, Taipei, Taiwan; Department of Oral Diagnosis and Pathology, Tri-Service General Hospital, Taipei, Taiwan.
authors.forename: Yi-Shing
authors.initials: YS
authors.lastname: Shieh
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Fone-Ching
authors.initials: FC
authors.lastname: Hsiao
authors.affiliation: School of Public Health, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Fu-Huang
authors.initials: FH
authors.lastname: Lin
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address: 10324@yahoo.com.tw.
authors.forename: Chang-Hsun
authors.initials: CH
authors.lastname: Hsieh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012727:Sex Characteristics; D055815:Young Adult; D000099255:Growth Arrest-Specific Protein 6
chemical_list: D012739:Gonadal Steroid Hormones; D036341:Intercellular Signaling Peptides and Proteins; D000099255:Growth Arrest-Specific Protein 6
keywords: Estradiol; Growth arrest-specific protein 6; Testosterone and ages