title: Abnormalities of the hypothalamo-pituitary-gonadal axis after head injury.
abstract: OBJECTIVE
  We aimed to investigate the mechanisms of hypogonadism which develops after head injury.
  
  
  METHODS
  Pulsatile secretion of LH was studied in subjects 6-10 days after major head injury.
  
  
  METHODS
  We studied five male subjects admitted with major head injuries and six healthy age-matched control subjects.
  
  
  METHODS
  During the pulsatility study, LH was measured at 5-minute intervals for 4 hours and 15-minute intervals for a further 2 hours. In addition, testosterone and LH were measured on Days 1-5, 14 and after 3-6 months.
  
  
  RESULTS
  The analysis of pulsatile secretion of LH demonstrated an LH pulse frequency similar to control subjects, but a significantly reduced LH pulse amplitude (P less than 0.001, fixed threshold method; P less than 0.02, Detect method). Both testosterone and LH levels were reduced after injury with the nadir occurring on Day 4.
  
  
  CONCLUSIONS
  Hypogonadism after head injury is due to defective LH secretion, with normal pulse frequency but a reduced pulse amplitude.
authors.affiliation: Department of Medicine, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: J D
authors.initials: JD
authors.lastname: Clark
authors.forename: P R
authors.initials: PR
authors.lastname: Raggatt
authors.forename: O M
authors.initials: OM
authors.lastname: Edwards
mesh_terms: D000328:Adult; D006259:Craniocerebral Trauma / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007006:Hypogonadism / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology*; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012636:Secretory Rate / Q000502:physiology; D013737:Testis / Q000503:physiopathology; D013739:Testosterone / Q000378:metabolism; D013997:Time Factors
chemical_list: D013739:Testosterone; D007986:Luteinizing Hormone