title: The Testicular Hormones AMH, InhB, INSL3, and Testosterone Can Be Independently Deficient in Older Men.
abstract: BACKGROUND
  Late-onset hypogonadism is symptomatically diverse and not fully explained by circulating testosterone level. The adult testes secrete four distinct hormones (testosterone, AMH, INSL3, and InhB) into the circulation. Testosterone and InhB have proven dynamic regulation, with limited information available for AMH and INSL3. During aging, there is cellular senescence, which may underlie the diversity of hypogonadism. This leads to the postulate that the relative levels (profile) of the four testicular hormones in older men are variable and cannot be evaluated by the measurement of one hormone.
  
  
  METHODS
  111 men aged 19-50 years and 98 men aged 70-90 years were examined. The circulating levels of the testicular hormones were measured using ELISAs, and the variation in the levels of hormones was analyzed by various correlative analyses.
  
  
  RESULTS
  All four hormones were largely or totally independent. Some men were deficient in multiple hormones, but no man had multiple elevated hormones. The average hormonal levels were lower in older men, with diverse profiles of the four testicular hormones. Hence, some men had one or more hormones below the reference range, with testosterone the most conserved. Consequently, testosterone levels were not indicative of the complete state of the endocrine testes.
  
  
  CONCLUSIONS
  The four hormones vary independently of each other, in younger and older men. This indicates that they are regulated dynamically rather than influenced by endocrine cell number. Older men exhibited diverse profiles of low levels of testicular hormones, suggesting that the testes age differently between men. Testosterone alone inadequately describes gonadal states.
authors.affiliation: Department of Anatomy, Otago School of Medical Sciences, Dunedin, New Zealand.|Department of Medicine, Dunedin School of Medicine, New Zealand.
authors.forename: Yih Harng
authors.initials: YH
authors.lastname: Chong
authors.affiliation: Department of Anatomy, Otago School of Medical Sciences, Dunedin, New Zealand.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Pankhurst
authors.affiliation: Department of Anatomy, Otago School of Medical Sciences, Dunedin, New Zealand.|Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
authors.forename: Ian S
authors.initials: IS
authors.lastname: McLennan
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D054304:Anti-Mullerian Hormone / Q000097:blood / Q000172:deficiency; D003430:Cross-Sectional Studies; D006801:Humans; D007265:Inhibins / Q000097:blood / Q000172:deficiency*; D007328:Insulin / Q000097:blood / Q000172:deficiency*; D008297:Male; D008875:Middle Aged; D011506:Proteins; D013735:Testicular Hormones / Q000097:blood / Q000172:deficiency*; D013739:Testosterone / Q000097:blood / Q000172:deficiency*; D055815:Young Adult
chemical_list: D007328:Insulin; C084797:Leydig insulin-like protein; D011506:Proteins; D013735:Testicular Hormones; C422364:inhibin B; D013739:Testosterone; D007265:Inhibins; D054304:Anti-Mullerian Hormone
keywords: Endocrinology; Late onset hypogonadism; Leydig cell; Sertoli cell; Testicular hormones