Brain natriuretic peptide at altitude: relationship to diuresis, natriuresis, and mountain sickness.
BACKGROUND
Acute mountain sickness (AMS) affects some new arrivals above an altitude of 2500 m. Hypobaric hypoxia is known to produce diuresis and has natriuretic effects due to the release of natriuretic peptides. We tested the hypothesis that increases in brain natriuretic peptide (BNP) at altitude correlates with increased urination and natriuresis as well as symptomatic AMS.


METHODS
Subjects were 14 mountaineers who undertook a Himalayan expedition that began at 100 m and passed through 3440 m en route to a final altitude of 5050 m. We measured the severity of AMS (Lake Louise Score), BNP values, nocturnal urine volume, and urine sodium concentration.


RESULTS
Nocturnal urine volume increased from 490 +/- 90 mi at 3440 m to 1100 +/- 104 ml at 5050 m. BNP levels at the higher altitude were 10.6 +/- 4.7 pg x ml(-1) and were correlated with the severity of AMS in all mountaineers (Lake Louise Score 4 +/- 0.5 for AMS subjects). However, AMS severity did not correlate with urine volume or urine sodium concentration.


CONCLUSIONS
Our results suggest that BNP secretion is not the cause of high-altitude diuresis. Further studies are needed to evaluate the possible role of BNP in individual responses to high altitude.
Feddersen
Berend
B
University of Munich, Klinikum Grosshadern, Department of Neurology, Marchioninistr. 15, D-81377 Munich, Germany. berend.feddersen@med.uni-muenchen.de
Ausserer
Harald
H
Haditsch
Bernd
B
Frisch
Herwig
H
Noachtar
Soheyl
S
Straube
Andreas
A
D000328:Adult; D000368:Aged; D000531:Altitude; D000532:Altitude Sickness / Q000097:blood* / Q000503:physiopathology; D004231:Diuresis / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009318:Natriuresis / Q000502:physiology*; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D014556:Urine; D055815:Young Adult
D020097:Natriuretic Peptide, Brain