title: Conjugated equine estrogens reverse the effects of aging on central and peripheral allopregnanolone and beta-endorphin levels in female rats.
abstract: OBJECTIVE
  To compare beta-endorphin and allopregnanolone levels and their response to a 2-week oral estrogen treatment with conjugated equine estrogens (CEE) in young ovariectomized (ovx) and in healthy aged female rats.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Animal laboratory in an academic environment.
  
  
  METHODS
  Twenty-four young ovx and 24 healthy aged female Wistar rats were treated with CEE. Three 8-rat control groups (cycling, ovx, and aged rats) were also included.
  
  
  METHODS
  Treated rats underwent 14-day oral treatment with three doses of CEE: 0.1 mg/kg/day, 0.5 mg/kg/day, and 2 mg/kg/day.
  
  
  METHODS
  Cerebral and peripheral beta-endorphin and allopregnanolone levels.
  
  
  RESULTS
  Beta-endorphin levels were lower in aged vs. cycling and ovx control rats. In brain and serum allopregnanolone levels were lower in aged vs. cycling control rats, whereas in the adrenals they were higher in aged vs. cycling animals. In the hypothalamus and anterior pituitary allopregnanolone levels were lower in ovx vs. aged animals. In both ovx and aged animals, CEE treatment reverted the effects of ovariectomy and aging, in a dose-dependent manner.
  
  
  CONCLUSIONS
  Aging is associated with a decrease in cerebral and peripheral beta-endorphin and allopregnanolone. In hypoestrogenic rats, CEE treatment restores allopregnanolone and beta-endorphin content; this indicates a role for these compounds as neuroendocrine mediators of the effects of estrogens.
authors.affiliation: Department of Reproductive Medicine and Child Development, P. Fioretti Division of Obstetrics and Gynecology, University of Pisa, Via Roma 35, 56100 Pisa, Italy. a.genazzani@obgyn.med.unipi.it
authors.forename: Andrea R
authors.initials: AR
authors.lastname: Genazzani
authors.forename: Massimo
authors.initials: M
authors.lastname: Stomati
authors.forename: Francesca
authors.initials: F
authors.lastname: Bernardi
authors.forename: Stefano
authors.initials: S
authors.lastname: Luisi
authors.forename: Elena
authors.initials: E
authors.lastname: Casarosa
authors.forename: Simone
authors.initials: S
authors.lastname: Puccetti
authors.forename: Alessandro D
authors.initials: AD
authors.lastname: Genazzani
authors.forename: Marco
authors.initials: M
authors.lastname: Palumbo
authors.forename: Michele
authors.initials: M
authors.lastname: Luisi
mesh_terms: D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000172:deficiency; D004966:Estrogens, Conjugated (USP) / Q000008:administration & dosage / Q000494:pharmacology*; D004971:Estrus; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D010052:Ovariectomy; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D011280:Pregnanolone / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution; D001615:beta-Endorphin / Q000097:blood / Q000378:metabolism*
chemical_list: D004967:Estrogens; D004966:Estrogens, Conjugated (USP); D001615:beta-Endorphin; D011280:Pregnanolone