Abstract
We have studied the integrated neuroendocrine and haemodynamic effects of acute hypoxaemia in ten healthy volunteers studied on two separate occasions. After reaching a resting haemodynamic state, subjects breathed either room air or a nitrogen/oxygen mixture which rendered arterial oxygen saturation between 75% and 80%. Measurements of pulmonary and systemic haemodynamics were made and blood samples taken at baseline and after 30 min breathing air or the hypoxic gas. Blood was assayed for plasma sodium and potassium, renin-angiotensin-aldosterone system activity, natriuretic peptides, cortisol and catecholamines. Hypoxaemia significantly increased heart rate, cardiac output and mean pulmonary artery pressure (P pa), but not mean arterial pressure compared with normoxaemia. Although plasma renin activity, angiotensin II and cortisol were unaffected by hypoxaemia, plasma aldosterone fell significantly in comparison with normoxaemia. This was associated with an increase in plasma atrial natriuretic peptide (ANP) but not b-type natriuretic peptide (BNP) during hypoxaemia whilst no changes were observed during normoxaemia. The increase in plasma ANP correlated positively with the increase inP pa. During hypoxaemia there is therefore dissociation of the renin-angiotensin-aldosterone system where plasma aldosterone decreased, despite there being no effects on plasma renin activity and angiotensin II or on plasma cortisol. This dissociation may be due to increased levels of ANP but not BNP having specific inhibitory effects on aldosterone biosynthesis. ANP increased in proportion to the degree of pulmonary vasoconstriction induced by hypoxaemia which may indicate a counter-regulatory role.
Similar content being viewed by others
References
Anand IS, Chandrashekhar Y, Ferrari R, Sarma R, Guleria R, Jindal SK, Wahi PL, Poole-Wilson PA, Harris P (1992) Pathogenesis of congestive state in chronic obstructive pulmonary disease. Circulation 86:12–21
Bold AJ de, Borenstein HB, Veress AT, Sonnenberg H (1981) A rapid and potent natriuretic response to intravenous injection of atria] myocardial extracts in rats. Life Sci 28:89–94
Brown MJ, Jenner DA (1981) Novel double isotope technique for enzymatic assay of catecholamines permitting high-precision sensitivity and plasma sample capacity. Clin Sci 61:591–598
Brown RA, Beck JS (1990) Comparison of several groups: the analysis of variance. In: Medical statistics on microcomputers. British Medical Journal, London, pp 34–42
Cargill RI, Lipworth BJ (1995) Pulmonary vasorelaxant effects of ANP and BNP in man. Thorax 50:183–185
Cargill RI, Coutie WJ, Lipworth BJ (1994) The effects of angiotensin II on circulating levels of natriuretic peptides. Br J Clin Pharmacol 38:139–142
Cargill RI, Struthers AD, Lipworth BJ (1995) Comparative effects of ANP and BNP on the aldosterone and pressor responses to angiotensin II in man. Clin Sci 88:81–86
Coats AJS (1990) Doppler ultrasonic measurement of cardiac output: reproducibility and validation. Eur Heart J 11 [Suppl 1]:49–61
Colice GL, Ramirez G (1985) Effect of hypoxaemia on the renin-angiotensin aldosterone system in humans. J Appl Physiol 58:724–730
Cutaia M, Rounds S (1990) Hypoxic pulmonary vasoconstriction: physiologic significance, mechanism and clinical relevance. Chest 97:706–718
Dabestani A, Mahan G, Gardin JM, Takenaka K, Burn C, Allfie A, Henry WL (1987) Evaluation of pulmonary artery pressure and resistance by pulsed Doppler echocardiography. Am J Cardiol 59:662–668
Euler US von, Liljestrand G (1946) Observations on the pulmonary arterial blood pressure in the cat. Acta Physiol Scand 12:301–320
Hosoda K, Nakao K, Mukoyama M, Saito Y, Jougasaki M, Shirakami G, Saga S, Ogawa Y, Yasue H, Imura H (1991) Expression of brain natriuretic peptide gene in human heart: production in the ventricle. Hypertension 17:1152–1156
Kawashima A, Kubo K, Kobayashi T, Sekiguchi M (1989) Haemodynamic responses to acute hypoxia, hypobaria and exercise in subjects susceptible to high altitude pulmonary edema. J Appl Physiol 67:1982–1989
Kawashima A, Kubo K, Matsuzawa Y, Kobayashi T, Sekiguchi M (1992) Hypoxia induced ANP secretion in subjects susceptible to high altitude pulmonary edema. Respir Physiol 89:309–317
Lang CC, Coutie WJ, Struthers AD, Dhillon DP, Winter JH, Lipworth BJ (1992) Elevated levels of brain natriuretic peptide in acute hypoxaemic chronic obstructive pulmonary disease. Clin Sci 83:529–533
Lawrence DL, Skatrud JB, Shenker Y (1990) Effect of hypoxia on atrial natriuretic factor and aldosterone regulation in humans. Am J Physiol 258:E243-E248
Lipworth BJ, Dagg KD (1994) Comparative effects of angiotensin II on Doppler parameters of left and right heart systolic and diastolic blood flow. Br J Clin Pharmacol 37:273–278
McMurray J, Coutie WJR, McFarlane L, Struthers AD (1988) Atrial natriuretic factor inhibits ACTH stimulated aldosterone, but not cortisol, secretion in man. Eur J Clin Pharmacol 35:409–412
Milledge JS (1992) Salt and water control at altitude. Int J Sports Med [Suppl] 13 S61-S63
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cargill, R.I., McFarlane, L.C., Coutie, W.J. et al. Acute neurohormonal responses to hypoxaemia in man. Europ. J. Appl. Physiol. 72, 256–260 (1996). https://doi.org/10.1007/BF00838648
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00838648