title: Characteristics of novel hair-based biomarker for the activity assessment of 11β-hydroxysteroid dehydrogenase.
abstract: BACKGROUND
  The ratio of hair cortisol to cortisone (R(hcc)) would be a potential biomarker to assess long-term activity of 11β-hydroxysteroid dehydrogenase (11β-HSD). Hair cortisol concentration in human varied with positions of hair segments in hair shaft, head locations of hair sampling and treatment methods of hair samples. However, currently unknown is whether these factors influence the determination of R(hcc) value.
  
  
  METHODS
  Hair strands longer than 4 cm in the posterior vertex collected from cohort A were used for segment analysis of R(hcc) and the 1-cm hair segments proximal to the scalp in the left section, right section and vertex from cohort B for location analysis and in the posterior vertex from cohort C for the effect of method on R(hcc). Hair cortisol and cortisone concentrations were measured with high performance liquid chromatography-tandem mass spectrometry.
  
  
  RESULTS
  R(hcc) showed no significant differences among different head locations and successive hair segments, but depended on the incubation duration in methanol and the milling step of hair samples.
  
  
  CONCLUSIONS
  R(hcc) was not affected by external environmental factors which gave rise to wash-out effect of hair cortisol and cortisone. R(hcc) would be a new underlying biomarker to reliably reflect long-term activity of 11β-HSD.
authors.affiliation: Research Center for Learning Science, Southeast University, Nanjing 210096, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Jifeng
authors.initials: J
authors.lastname: Li
authors.forename: Youyun
authors.initials: Y
authors.lastname: Xu
authors.forename: Jin
authors.initials: J
authors.lastname: Yang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.forename: Huihua
authors.initials: H
authors.lastname: Deng
mesh_terms: D042842:11-beta-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003348:Cortisone / Q000032:analysis*; D004789:Enzyme Activation; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D053719:Tandem Mass Spectrometry; D055815:Young Adult
chemical_list: D015415:Biomarkers; D042842:11-beta-Hydroxysteroid Dehydrogenases; D003348:Cortisone; D006854:Hydrocortisone
keywords: 11β-hydroxysteroid dehydrogenase; Hair cortisol; Hair cortisone; Tandem mass spectrometry; The ratio of cortisol to cortisone