Document Detail


17beta-estradiol effect on critical cardiac output with reduction of cardiac output in oophorectomized sheep.
MedLine Citation:
PMID:  9688896     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Acute administration of 17beta-estradiol (E2beta) leads to increases in cardiac output, oxygen delivery, and oxygen consumption and increases the critical cardiac output in the nonpregnant sheep. We sought to determine whether the lack of a critical cardiac output or flow-dependent oxygen consumption during states of low cardiac output in late gestation can be reproduced in nonpregnant sheep treated with estrogen. We studied five nonpregnant oophorectomized sheep in a randomized crossover design by placing catheters in the pulmonary artery, the right atrium, and the descending aorta. Three experiments were randomly performed on each sheep 3 to 5 days apart: 1) without estrogen or vehicle, 2) 2-3 h after intravenous administration of vehicle, and 3) 2-3 h after intravenous E2beta (3 microg/kg). Cardiac output was gradually reduced while hemodynamic, cardiorespiratory, acid-base, and metabolic variables were simultaneously evaluated. There was a 70% increase in cardiac output in animals given E2beta compared with that in the same animals given either vehicle or nothing (194.0 +/- 13.0, 120.0 +/- 14.5, and 114.0 +/- 16.2 ml . min-1 . kg-1, respectively; P < 0.05). Oxygen consumption was twofold higher in the E2beta series compared with that in the no-treatment and vehicle series (10.01 +/- 1.3, 6.04 +/- 0.77, and 4.52 +/- 0.42 ml O2 . min-1 . kg-1, respectively; P < 0. 05). Tissue oxygen extraction was unaltered by estrogen. However, tissue oxygen extraction at the critical cardiac output was lower in the estradiol group. In relation to oxygen consumption, all three groups demonstrated a critical cardiac output when cardiac output was gradually reduced. However, the level of critical cardiac output was significantly higher in the E2beta group (68.4 +/- 2.4, 42.8 +/- 2.6, and 46.2 +/- 2.6 ml . min-1 . kg-1, respectively; P < 0.05). We conclude that E2beta exhibits increases in systemic tissue blood flow and oxygen consumption. Animals given E2beta show increases in critical cardiac output and impairment of tissue oxygen extraction at critical cardiac output, which leads to development of flow-dependent oxygen consumption at higher cardiac outputs than in the control animals.
Authors:
W Evans; T M Phernetton; R R Magness
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  275     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Jul 
Date Detail:
Created Date:  1998-08-27     Completed Date:  1998-08-27     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H57-64     Citation Subset:  IM    
Affiliation:
Perinatal Research Laboratories, Department of Obstetrics and Gynecology, University of Wisconsin Medical School, Madison 53792, Wisconsin.
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MeSH Terms
Descriptor/Qualifier:
Animals
Aorta / drug effects,  physiology
Blood Glucose / drug effects,  metabolism
Blood Pressure / drug effects
Cardiac Output / drug effects,  physiology*
Cross-Over Studies
Estradiol / pharmacology*
Female
Heart Rate / drug effects
Hemodynamics / drug effects,  physiology*
Lactates / blood
Ovariectomy*
Oxygen / blood
Oxygen Consumption / drug effects
Pulmonary Artery / drug effects,  physiology
Random Allocation
Reference Values
Regression Analysis
Sheep
Grant Support
ID/Acronym/Agency:
HL-33255/HL/NHLBI NIH HHS; HL-49210/HL/NHLBI NIH HHS; HL-57653/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Lactates; 50-28-2/Estradiol; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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