title: Estrogen acutely increases peripheral blood flow in postmenopausal women.
abstract: OBJECTIVE
  To test the acute effect of estrogen on peripheral blood flow and vascular resistance in postmenopausal women.
  
  
  METHODS
  Eleven normotensive, post-menopausal female volunteers (mean age 53 +/- 6 years) were studied. Six women were in natural menopause and 5 had had a hysterectomy (mean age of the menopause 49 +/- 3 years). We used a double-blind, randomized protocol to assess the acute response to sublingual estradiol-17 beta (1 mg) on the forearm resistance vessels, compared with sublingual placebo. Blood flow was measured by strain-gauge plethysmography, and mean peripheral vascular resistance was then calculated. Mean blood pressure was also measured.
  
  
  RESULTS
  The mean blood flow induced by estradiol-17 beta after 40 minutes was significantly greater than that induced by placebo (3.9 +/- 0.5 mL/100 mL per minute versus 2.4 +/- 0.4 mL/100 mL per minute, respectively, P < 0.05). The forearm resistance was significantly reduced at 40 minutes after estradiol-17 beta compared with placebo (25.7 +/- 4.4 resistance units (RU) to 44.4 +/- 6.4 RU, respectively, P < 0.05). Mean blood pressure 40 minutes after the administration of estradiol-17 beta was no different when compared with placebo (91 +/- 1.5 mm Hg versus 90 +/- 2.5 mm Hg, respectively, P = NS).
  
  
  CONCLUSIONS
  These results indicate that the acute administration of estradiol-17 beta affects blood flow in the peripheral vasculature in human subjects. The mechanism of this effect has not been determined, but it may explain some of the beneficial effects of estrogen on the vascular system and have future therapeutic potential in postmenopausal women.
authors.affiliation: Department of Cardiac Medicine, National Heart and Lung Institute, London, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Volterrani
authors.forename: G
authors.initials: G
authors.lastname: Rosano
authors.forename: A
authors.initials: A
authors.lastname: Coats
authors.forename: C
authors.initials: C
authors.lastname: Beale
authors.forename: P
authors.initials: P
authors.lastname: Collins
mesh_terms: D000286:Administration, Sublingual; D001783:Blood Flow Velocity / Q000502:physiology; D004311:Double-Blind Method; D004958:Estradiol / Q000008:administration & dosage / Q000502:physiology*; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology*; D012016:Reference Values; D014655:Vascular Resistance / Q000502:physiology
chemical_list: D004958:Estradiol