title: Pituitary dysfunction in recently post-menopausal women. Nottingham EPIC Study Group.
abstract: OBJECTIVE
  Some recently post-menopausal women have lower than expected FSH concentrations, raising the possibility of subclinical hypothalamo-pituitary impairment. We have therefore performed pituitary stimulation tests in a group of recently post-menopausal women recruited to a bone loss prevention study.
  
  
  METHODS
  Prospective study of health volunteers.
  
  
  METHODS
  Outpatient, teaching hospital in Nottingham UK.
  
  
  METHODS
  Forty-seven women selected from a cohort of 428 healthy volunteers to an osteoporosis prevention study all within 10 years of the menopause.
  
  
  METHODS
  Response of the pituitary to formal stimulation tests and its relationship to bone mineral density.
  
  
  RESULTS
  A significantly attenuated response to pituitary stimulation was found in a group of otherwise healthy women with an FSH considered to be inappropriately low for the level of circulating oestradiol. The impaired responses were significant not only for FSH as expected but also to LH and prolactin at 1 hour after injection of GnRH and TRH (area under the curve, FSH P = 0.01, LH P = 0.001, prolactin P < 0.0001). TSH secretion was not significantly impaired. Baseline cortisol, growth hormone and thyroxine (T4) were normal in both control and test subjects. The test group was both heavier and taller, with a higher lean body mass, a higher body mass index and a greater total body fat than the controls. Bone mineral density showed no significant differences between the groups. Test subjects also had a higher free oestradiol index (P < 0.001) which correlated strongly (r = 0.534, P = 0.00026) with baseline FSH levels and possibly reflects a greater tissue exposure to biologically active hormone. Oestrone concentrations were, however, no different between the groups.
  
  
  CONCLUSIONS
  Serum FSH concentrations are not invariably elevated in recently post-menopausal women and use of FSH as a determinant for postmenopausal status in clinical trials should be used with caution. Notwithstanding their higher free oestradiol index, women found to have an abnormally low basal FSH had evidence of poor prolactin, FSH and LH but not TSH responses to pituitary stimulation. This may represent either a degree of subclinical pituitary failure of a variant of normal. The low levels of gonadotrophin activity did not affect bone mineral density.
authors.affiliation: Medical Research Centre, Nottingham City Hospital, UK.
authors.forename: A
authors.initials: A
authors.lastname: Lyons
authors.forename: C
authors.initials: C
authors.lastname: Ng
authors.forename: K
authors.initials: K
authors.lastname: Fielding
authors.forename: D
authors.initials: D
authors.lastname: Hosking
authors.forename: C
authors.initials: C
authors.lastname: Selby
authors.forename: N
authors.initials: N
authors.lastname: Lawson
mesh_terms: D015519:Bone Density / Q000502:physiology; D015331:Cohort Studies; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008875:Middle Aged; D010901:Pituitary Function Tests; D010902:Pituitary Gland / Q000503:physiopathology*; D017698:Postmenopause / Q000097:blood / Q000502:physiology*; D011446:Prospective Studies; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D018709:Statistics, Nonparametric; D013972:Thyrotropin; D013974:Thyroxine / Q000097:blood
chemical_list: D012738:Sex Hormone-Binding Globulin; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D013974:Thyroxine; D006854:Hydrocortisone