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Ventricular performance and glucose uptake in rats during chronic hypobaric hypoxia
W E Hurford1, G Crosby, H W Strauss
1Anesthesia Service, Massachusetts General Hospital, Boston 02114.
Summary
Hypobaric hypoxia impairs right ventricular function and increases myocardial glucose uptake in rats, particularly in the right ventricle. Recovery partially restores ventricular performance but not glucose uptake patterns.
Area of Science:
- Cardiovascular Physiology
- Metabolic Research
Background:
- Hypobaric hypoxia poses significant stress on the cardiovascular system.
- Understanding myocardial metabolic adaptations is crucial for managing high-altitude physiology.
Purpose of the Study:
- To investigate the impact of hypobaric hypoxia on ventricular performance.
- To examine changes in myocardial glucose uptake in response to hypoxia.
- To explore the relationship between ventricular function and glucose metabolism.
Main Methods:
- Radionuclide angiocardiography was used to assess ventricular ejection fraction.
- 2-[14C]deoxyglucose (2-[14C]DG) autoradiography measured myocardial glucose uptake.
- Studies were conducted on control, hypoxic, and recovered Sprague-Dawley rats.
Main Results:
- Right ventricular ejection fraction significantly decreased during hypoxia (40%) compared to controls (66%) and recovered rats (60%).
- Left ventricular ejection fraction remained unchanged.
- Myocardial glucose uptake increased during hypoxia, with a disproportionately greater increase in the right ventricle compared to the left ventricle and septum.
- Altered right ventricular glucose uptake correlated with increased systolic pulmonary artery pressure.
Conclusions:
- Hypobaric hypoxia leads to impaired right ventricular function and altered myocardial glucose metabolism.
- The right ventricle shows a heightened metabolic response to hypoxia.
- These changes are linked to elevated pulmonary artery pressure.