Exhalation of gaseous nitric oxide by rats in response to endotoxin
and its absorption by the lungs.
Stitt, John T., Arthur B. Dubois, James S. Douglas, and Steven G.
Shimada.
The John B. Pierce Foundation Laboratory, Yale University School of
Medicine, New Haven, CT 06519
APStracts 3:0441A, 1996.
Rats injected with a lipopolysaccharide (LPS) endotoxin, produce
detectable concentrations of nitric oxide gas (NO) in the expired air
within 60 minutes. The concentration of NO reaches a plateau at + 3
hours. Production of the NO is dose dependent upon LPS and at a dose
of 1 mg/kg, i.v., LPS alveolar concentrations of >260 parts
per billion (ppb) are observed. Nitric oxide synthase (NOS)
inhibitors suppress this NO production in response to endotoxin.
Experiments were conducted to ascertain the site of origin of this NO
and to measure the capacity of the lungs to absorb NO from alveolar
air. Results indicate that the endotoxin-induced NO originates from
within the lungs themselves and that the lungs have the capacity to
absorb more than 60% of NO that is presented to them. Lung tissues
absorb about 44 - 47% of the NO load, blood carries away between 15
and 19%, whilst the remainder is exhaled in the expired air. It is
proposed that the exhalation of NO might prove useful as an early
biomarker for acute lung injury.
Received 9 April 1996; accepted in final form 10 September 1996.
APS Manuscript Number A334-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 7 October 1996