title: Effects of long-term oral hormone replacement therapy on plasma nitric oxide and beta-endorphin levels in postmenopausal women.
abstract: OBJECTIVE
  The aim of this study is to evaluate the relationship between plasma nitric oxide (NO) and beta-endorphin levels in women using hormone replacement therapy (HRT) for 12 months.
  
  
  METHODS
  Our study group was composed of 55 patients who were in at least their second postmenopausal year. Of the 55 patients, 25 were in the control group. All 30 women in the study group received 2 mg 17beta-estradiol + 1 mg norethisterone acetate tablets daily for 12 months. Plasma NO and beta-endorphin levels were measured both before and after the study period and possible relationships were analyzed.
  
  
  RESULTS
  There was a significant increase in both beta-endorphin (p = 0.0001, 10.93 +/- 2.25 vs. 14.85 +/- 2.49) and NO (p = 0.0001, 19.79 +/- 4.01 vs. 27.83 +/- 10.27) levels measured after the study in the HRT group. A correlation was seen between the increments in beta-endorphin and NO levels in the HRT group.
  
  
  CONCLUSIONS
  Continuous combined HRT raises both plasma NO and beta-endorphin levels and a close relationship was found between the two molecules after therapy. We postulate that the increment in these molecules may explain some of the beneficial effects of HRT on cognitive function and mood.
authors.affiliation: Gynecology and Obstetrics Department, Istanbul Medical Faculty, University of Istanbul, Istanbul, Turkey. akhan93@hotmail.com
authors.forename: Süleyman E
authors.initials: SE
authors.lastname: Akhan
authors.forename: Tülin
authors.initials: T
authors.lastname: Gürel
authors.forename: Recep
authors.initials: R
authors.lastname: Has
authors.forename: Ahmet Cem
authors.initials: AC
authors.lastname: Iyibozkurt
authors.forename: Abdullah
authors.initials: A
authors.lastname: Turfanda
mesh_terms: D015992:Body Mass Index; D004958:Estradiol / Q000097:blood; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood*; D017698:Postmenopause; D001615:beta-Endorphin / Q000097:blood*
chemical_list: D009569:Nitric Oxide; D004958:Estradiol; D001615:beta-Endorphin