title: Reduction in amino-acid-induced anti-hypothermic effects during general anesthesia in ovariectomized rats with progesterone replacement.
abstract: OBJECTIVE
  The aim of the present study was to determine whether the ovarian hormones, estrogen and progesterone, had different influences on amino-acid-induced anti-hypothermic effects during general anesthesia.
  
  
  METHODS
  Ovariectomized Sprague-Dawley female rats were divided into four groups: those administered 17β-estradiol plus saline or an amino acid mixture (E2-Sal and E2-AA, respectively) and progesterone plus saline or an amino acid mixture (P-Sal and P-AA, respectively). Five weeks after ovariectomy, rats were given either E2 or P and then administered either Sal or AA solution for 180 min during anesthesia with sevoflurane. Rectal temperatures were measured.
  
  
  RESULTS
  Rectal temperatures were significantly higher in the E2-AA group than in the E2-Sal group 165 and 180 min after initiating the infusion of the test solutions. However, no significant differences were observed between the P-treated groups. The phosphorylation of 4E-BP1 and S6K1 was significantly greater in the E2-AA group than in the E2-Sal group (P < 0.05, P < 0.001, respectively). In contrast, the phosphorylation of 4E-BP1 was significantly lower in the P-AA group than in the P-Sal group (P < 0.001).
  
  
  CONCLUSIONS
  These results suggest that progesterone reduces amino-acid-induced anti-hypothermic effects during general anesthesia.
authors.affiliation: Division of Anesthesia, Tokai University Oiso Hospital, 21-1 Gakkyo, Oiso-machi, Naka-gun, Kanagawa, 259-0198, Japan. kanazawa@is.icc.u-tokai.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kanazawa
authors.affiliation: Division of Anesthesia, Tokai University Oiso Hospital, 21-1 Gakkyo, Oiso-machi, Naka-gun, Kanagawa, 259-0198, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Anesthesiology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1143, Japan.
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage*; D000768:Anesthesia, General / Q000379:methods*; D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007035:Hypothermia / Q000517:prevention & control*; D008738:Methyl Ethers / Q000008:administration & dosage; D010052:Ovariectomy; D010766:Phosphorylation / Q000187:drug effects; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077149:Sevoflurane
chemical_list: D000596:Amino Acids; D008738:Methyl Ethers; D000077149:Sevoflurane; D011374:Progesterone; D004958:Estradiol
keywords: Amino acids; Female sex hormones; General anesthesia; Hypothermia