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Hypoxia-induced arterial endothelin does not influence peripheral vascular tone
G J Blauw1, R G Westendorp, N Srivastava
1Department of General Internal Medicine, University Hospital Leiden, The Netherlands.
Journal of Cardiovascular Pharmacology
|January 1, 1995
Summary
Hypoxia (low oxygen) increases endothelin-1 (ET) levels in the blood but does not affect forearm blood flow. This suggests ET release from the lungs, not peripheral influence, during hypoxia.
Area of Science:
- Cardiovascular Physiology
- Respiratory Physiology
Background:
- Endothelin-1 (ET) is a potent vasoconstrictor.
- The effects of hypoxia on ET production and peripheral vascular tone are not fully understood.
Purpose of the Study:
- To investigate the impact of hypoxia on endothelin-1 (ET) production in the forearm.
- To determine the vascular effects of intra-arterially administered ET during normoxia.
Main Methods:
- Six healthy volunteers underwent hypoxia (SpO2 80%).
- Arteriovenous ET levels and forearm blood flow (FBF) were measured.
- Eight subjects received intra-arterial ET infusion during normoxia.
Main Results:
- Hypoxia increased arterial ET plasma levels (2.5 to 3.3 ng/L) but did not alter FBF.
- Intra-arterial ET infusion (0.5 pg/kg/min) raised arterial ET levels (2.2 to 4.9 ng/L) without affecting FBF.
- Venous ET levels remained unchanged during hypoxia.
Conclusions:
- Hypoxia stimulates endothelin-1 (ET) release, likely from the pulmonary vascular bed.
- Increased arterial ET levels during hypoxia do not influence peripheral vascular tone in the forearm.