Oestrogen changed cardiomyocyte contraction and beta-adrenoceptor expression in rat hearts subjected to ischaemia-reperfusion.
Women with functional ovaries have a lower cardiovascular risk than men and postmenopausal women. However, oestrogen replacement therapy remains controversial. This study examined the effect of ovarian hormone deficiency and oestrogen replacement on ventricular myocyte contractile function and expression of beta-adrenoceptors (beta-ARs). Female Sprague-Dawley rats were subjected to bilateral ovariectomy (OVX) or sham operation (Sham). A subgroup of OVX rats received oestrogen (E2) replacement (40 microg kg(-1) day(-1)) for 4 weeks. Cardiomyocyte shortening was evaluated in basal conditions and in the presence of isoprenaline (ISO). The expression of beta-ARs was assessed by Western blotting. The presence of lactate dehydrogenase (LDH) activity in the coronary effluent was determined. Ovariectomy promoted body weight gain associated with reduced serum E2 and uterine weight, all of which were abolished by treatment with E2. Ovariectomy increased the amplitude of both basal and ISO-stimulated contractions, increased LDH release, upregulated beta1-AR expression and downregulated beta2-AR expression, all of which were restored by treatment with E2. A beta1-AR antagonist, CGP20712A, but not a beta2-AR antagonist, ICI118,551, significantly decreased the amplitude of ventricular myocyte shortening. Oestrogen decreased cardiomyocyte contraction and the expression of beta1-AR, and increased expression of beta2-AR, and all these effects were abolished by the E2 receptor antagonist, ICI182,780. These data suggest that oestrogen plays a cardioprotective role in female rat hearts subjected to ischaemia-reperfusion injury, and the effects of oestrogen are associated with decreased cardiomyocyte contraction and expression of beta1-AR, and increased expression of beta2-AR.
Wu
Qin
Q
Department of Physiology, Xuzhou Medical College, West Huaihai Road 84, Xuzhou, Jiangsu 221002, China. hhwuq@yahoo.com.cn
Zhao
Zhi
Z
Sun
Hong
H
Hao
Yan-ling
YL
Yan
Chang-dong
CD
Gu
Shu-ling
SL
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000502:physiology*; D005260:Female; D000077267:Fulvestrant; D007093:Imidazoles / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009200:Myocardial Contraction / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D010052:Ovariectomy; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism*
D000319:Adrenergic beta-Antagonists; D004965:Estrogen Antagonists; D004967:Estrogens; D007093:Imidazoles; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D000077267:Fulvestrant; C026777:ICI 118551; D004958:Estradiol; C049763:CGP 20712A; D007770:L-Lactate Dehydrogenase