title: Estrogen replacement stimulates fatty acid oxidation and impairs post-ischemic recovery of hearts from ovariectomized female rats.
abstract: Women less than 50 years of age, the majority of whom are likely premenopausal and exposed to estrogen, are at greater risk of a poor short-term recovery after myocardial ischemia than men and older women. Since estrogen enhances non-cardiac lipid utilization and increased lipid utilization is associated with poor post-ischemic heart function, we determined the effect of estrogen replacement on post-ischemic myocardial function and fatty acid oxidation. Female Sprague-Dawley rats, either intact (n = 15) or ovariectomized and treated with 17beta-estradiol (0.1 mg x kg(-1) x day(-1), s.c., n = 14) or corn oil vehicle (n = 16) for 5 weeks, were compared. Function and fatty acid oxidation of isolated working hearts perfused with 1.2 mM [9,10-3H]palmitate, 5.5 mM glucose, 0.5 mM lactate, and 100 mU/L insulin were measured before and after global no-flow ischemia. Only 36% of hearts from estrogen-treated rats recovered after ischemia compared with 56% from vehicle-treated rats (p > 0.05, not significant), while 93% of hearts from intact rats recovered (p < 0.05). Relative to pre-ischemic values, post-ischemic function of estrogen-treated hearts (26.3 +/- 10.1%) was significantly lower than vehicle-treated hearts (53.4 +/- 11.8%, p < 0.05) and hearts from intact rats (81.9 +/- 7.0%, p < 0.05). Following ischemia, fatty acid oxidation was greater in estrogen-treated hearts than in the other groups. Thus, estrogen replacement stimulates fatty acid oxidation and impairs post-ischemic recovery of isolated working hearts from ovariectomized female rats.
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of British Columbia, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC V6Z 1Y6, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Grist
authors.forename: Richard B
authors.initials: RB
authors.lastname: Wambolt
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Bondy
authors.forename: Dean R
authors.initials: DR
authors.lastname: English
authors.forename: Michael F
authors.initials: MF
authors.lastname: Allard
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000097:blood; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D006321:Heart / Q000187:drug effects / Q000503:physiopathology; D066298:In Vitro Techniques; D017202:Myocardial Ischemia / Q000378:metabolism / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010052:Ovariectomy; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004967:Estrogens; D005227:Fatty Acids; D004958:Estradiol