title: Serum FSH, LH, and testosterone concentrations in presumably fertile men: effect of age.
abstract: OBJECTIVE
  Delineation of change in male hormone and gonadotropin levels from age 21 to 85.
  
  
  METHODS
  Healthy married volunteers with one or more children.
  
  
  METHODS
  A 5-mL venous blood sample, serum separated within one hour; testosterone measured by direct RIA, FSH and LH by immunoradiometric assay and magnetic separation.
  
  
  RESULTS
  FSH significantly higher from 6th decade, LH from 7th decade; testosterone lower from 6th decade.
  
  
  CONCLUSIONS
  Apparently, a rise in FSH and reduction in testosterone precede a rise in LH concentration.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Colombo, Sri Lanka.
authors.forename: K H
authors.initials: KH
authors.lastname: Tennekoon
authors.forename: E H
authors.initials: EH
authors.lastname: Karunanayake
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D005298:Fertility / Q000502:physiology*; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006801:Humans; D015592:Immunoradiometric Assay; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone