title: Plasma concentrations of progesterone are higher in the uterine artery than in the radial artery after vaginal administration of micronized progesterone in an oil-based solution to postmenopausal women.
abstract: OBJECTIVE
  To verify the occurrence of preferential distribution of vaginally administered progesterone to the uterus compared with extrapelvic regions in vivo and in humans.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  University medical school.
  
  
  METHODS
  Twenty postmenopausal women undergoing transabdominal hysterectomy for benign pathologies.
  
  
  METHODS
  Forty-five minutes before surgery, the women received a single vaginal administration of an oil-based micronized progesterone (100 mg) solution currently available on the market for IM use. During the operation, parallel blood samples were drawn from the uterine and radial arteries.
  
  
  METHODS
  Plasma levels of progesterone were measured by RIA.
  
  
  RESULTS
  Mean (+/- SD) plasma levels of progesterone were significantly higher in the uterine artery than in the radial artery (9.75 +/- 3.21 vs. 5.12 +/- 2.06 ng/mL, respectively).
  
  
  CONCLUSIONS
  Vaginal administration allows a preferential distribution of progesterone to the uterus, which confirms the existence of the so-called "first uterine pass effect."
authors.affiliation: Department of Gynecology and Obstetrics, Medical School, University of Bari, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Cicinelli
authors.forename: M
authors.initials: M
authors.lastname: Cignarelli
authors.forename: S
authors.initials: S
authors.lastname: Sabatelli
authors.forename: F
authors.initials: F
authors.lastname: Romano
authors.forename: L M
authors.initials: LM
authors.lastname: Schonauer
authors.forename: R
authors.initials: R
authors.lastname: Padovano
authors.forename: N
authors.initials: N
authors.lastname: Einer-Jensen
mesh_terms: D000282:Administration, Intravaginal; D001158:Arteries; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D011374:Progesterone / Q000008:administration & dosage* / Q000097:blood*; D011446:Prospective Studies; D017534:Radial Artery; D012996:Solutions; D014599:Uterus / Q000098:blood supply*
chemical_list: D012996:Solutions; D011374:Progesterone