title: The temporal relationship between growth hormone and slow wave sleep is weaker after menopause.
abstract: OBJECTIVE
  To study the temporal association between growth hormone (GH) and slow wave sleep (SWS) in middle-aged women.
  
  
  METHODS
  Seventeen premenopausal and 18 postmenopausal women were studied using all-night polygraphic sleep recordings and blood sampling at 20-min intervals. The postmenopausal women were re-studied after six months on hormone therapy (HT) according to a randomized, double-blind, placebo-controlled protocol.
  
  
  RESULTS
  The total sleep time (premenopausal 361.9±81.5 min, postmenopausal 358±67.7 min) and the percentages of the sleep stages did not differ between pre- and postmenopausal women. In postmenopausal women the first GH peak after sleep onset occurred later and with a more variable time interval compared to premenopausal women. The percentage of SWS was highest 40-20 min prior to the first GH peak after sleep onset in both groups with a higher SWS proportion in premenopausal women (p=0.048), although the total SWS percent for night did not differ. HT did not affect the distribution of SWS in postmenopausal women.
  
  
  CONCLUSIONS
  The temporal relationship between GH and SWS in premenopausal women is less robust after menopause and is not improved with HT.
authors.affiliation: Sleep Research Unit, Department of Physiology, University of Turku, Finland. nea.kalleinen@utu.fi
authors.forename: Nea
authors.initials: N
authors.lastname: Kalleinen
authors.forename: Arho
authors.initials: A
authors.lastname: Virkki
authors.forename: Olli
authors.initials: O
authors.lastname: Polo
authors.forename: Sari-Leena
authors.initials: SL
authors.lastname: Himanen
authors.forename: Kerttu
authors.initials: K
authors.lastname: Irjala
authors.forename: Atte
authors.initials: A
authors.lastname: Joutsen
authors.forename: Tarja
authors.initials: T
authors.lastname: Porkka-Heiskanen
authors.forename: Päivi
authors.initials: P
authors.lastname: Polo-Kantola
mesh_terms: D016022:Case-Control Studies; D004311:Double-Blind Method; D004569:Electroencephalography / Q000187:drug effects; D015914:Estrogen Replacement Therapy; D005260:Female; D019382:Human Growth Hormone / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008593:Menopause / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D017286:Polysomnography / Q000187:drug effects; D012890:Sleep / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
chemical_list: D019382:Human Growth Hormone