ISSN:
1439-6327
Keywords:
Saliva
;
Aldosterone
;
Glucocorticoid
;
High altitude
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Saliva was collected from six healthy young men at hourly intervals at sea level and after 1–2, 8–9 and 15–16 days at 4450 m on Mount Kenya for measurement of aldosterone (SA) and glucocorticoid (SGC, cortisol + cortisone) concentrations. Blood samples were collected simultaneously with some of the saliva samples and analysis of these showed that plasma and saliva concentrations of aldosterone and glucocorticoids were highly correlated (r=0.91 and 0.75 respectively;p〈0.01 for both hormones). Mean SA for the group was reduced to approximately 50% of the sea-level value (p〈0.05) by the time the first saliva samples were collected at altitude, and remained at this depressed level throughout the 2-week period on Mount Kenya, although there was considerable inter-subject variation. SGC concentration also tended to be lower on Mount Kenya than at sea level. Though SA was lower throughout the day at altitude compared to sea level, the principal difference in the temporal pattern of SA was the reduction or complete absence of the marked rise in SA that normally occurs in the first few hours after rising. SA and SGC responses to exercise, which consisted of stepping on and off an 0.4-m high stool 60 times/min for 25 min, were assessed at sea level and after various periods at 4450 m. At altitude the SGC response was significantly enhanced, but the SA response was blunted. The exercise-induced increase in SA correlated with the mean diurnal SA of the previous or next day (r=0.74;p〈0.01). Our data indicate that at altitude there is a decrease in aldosterone response to both renin-angiotensin and ACTH stimulation, which suggests that hypobaric hypoxia has a direct, inhibitory effect upon the zona glomerulosa. They also demonstrate the usefulness of collecting saliva for the measurement of adrenocortical steroid concentrations during expeditions of this type, thus permitting the non-invasive monitoring of adrenocortical activity during real life situations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00643507
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