title: Age related variation of salivary testosterone values in healthy Japanese males.
abstract: OBJECTIVE
  We examined age associated variation in salivary testosterone values among Japanese males as well as anthropometric measurements.
  
  
  METHODS
  Salivary samples were collected in pretreated sodium azide treated tubes. The first series: 15-79-year-old males (n = 99); two morning and two evening samples were collected at home for two days. The second series: 90-year-old males (n = 29); one morning sample was collected. Testosterone values were determined using an iodine125-based radioimmunoassay kit modified for saliva.
  
  
  RESULTS
  Results show 1) a significant decrease in salivary testosterone values from 20s to 40s and older, 2) no significant decline after 40 through 90 years old, 3) no significant age-related differences in the degree of intraindividual diurnal fluctuation across age groups of 40-70s, and 4) higher BMI is associated with the lower salivary testosterone among 40-70s.
  
  
  CONCLUSIONS
  These results suggest that neither a constant decrease of salivary testosterone values or markedly reduced intraindividual fluctations are universal aspects of aging. Older males may maintain relatively high testosterone levels compared to younger men and a relatively 'robust' neuroendocrinological system.
authors.affiliation: School of International Liberal Studies, Waseda University, Japan. a.uchida@waseda.jp
authors.forename: Akiko
authors.initials: A
authors.lastname: Uchida
authors.forename: Richard G
authors.initials: RG
authors.lastname: Bribiescas
authors.forename: Peter T
authors.initials: PT
authors.lastname: Ellison
authors.forename: Masao
authors.initials: M
authors.lastname: Kanamori
authors.forename: Juko
authors.initials: J
authors.lastname: Ando
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Hirose
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ono
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012463:Saliva / Q000737:chemistry*; D013739:Testosterone / Q000032:analysis* / Q000378:metabolism
chemical_list: D013739:Testosterone