Effects of estrogen on venous function in rats with chronic heart failure.
The effect of 17beta-estradiol on venous function was investigated in ovariectomized rats with heart failure. Rats (50-60 days old) were ovariectomized and implanted with 60-day-release pellets that contain 17beta-estradiol (1.5 mg) or vehicle. The left coronary artery was ligated 7 days later. Another group of ovariectomized rats was given vehicle pellets and then a sham operation was performed. The rats were studied while under pentobarbital anesthesia at 7 wk after ligation. Ligated rats, relative to sham groups, had lower mean arterial pressure (MAP, -34 mmHg) and cardiac output (CO, -38%); higher arterial resistance (R(A), +12%) and venous resistance (R(V), +116%); mean circulatory filling pressure (MCFP, +40%) and left ventricular end-diastolic pressure (LVEDP, +11 mmHg); and similar cardiovascular responses to norepinephrine (NE). Treatment of ligated rats with 17beta-estradiol increased CO (+16%); reduced R(A) (-16%), R(V) (-35%), MCFP (-23%), and LVEDP (-3 mmHg); and augmented MAP, R(V,) and MCFP responses to NE. Therefore, 17beta-estradiol reduced MCFP, and this reduced preload (LVEDP). 17beta-Estradiol decreased R(V), which, along with decreased R(A) (afterload), led to an increase in CO. 17beta-Estradiol likely augmented vasoconstriction to NE through an improvement on the cardiovascular status.
Nekooeian
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Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
Pang
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D000818:Animals; D001775:Blood Circulation / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002303:Cardiac Output, Low / Q000503:physiopathology*; D002319:Cardiovascular System / Q000187:drug effects; D002908:Chronic Disease; D004958:Estradiol / Q000097:blood / Q000494:pharmacology; D004967:Estrogens / Q000502:physiology*; D005260:Female; D009638:Norepinephrine / Q000494:pharmacology; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014680:Veins / Q000187:drug effects / Q000503:physiopathology*
D004967:Estrogens; D004958:Estradiol; D009638:Norepinephrine