Increase in 6-hydroxymelatonin excretion in humans during ascent to high altitudes.
J Clin Endocrinol Metab
; 89(9): 4388-90, 2004 Sep.
Article
em En
| MEDLINE
| ID: mdl-15356035
ABSTRACT
Melatonin (MLT), the pineal gland hormone involved in the regulation of circadian rhythms, shows characteristic diurnal variation. Its physiological role in humans is not clear. Exposure to high altitudes may disrupt the circadian rhythm and lead to various endocrine changes. MLT in humans has not been studied under these conditions. Urinary 6-hydroxy-MLT sulfate (aMT6s) excretion was analyzed during the day (0700-2200 h) and night (2200-0700 h) phases. A cohort of 33 healthy volunteers, aged 19-65 yr, was studied during an ascent to a high altitude in the Himalayas on three occasions (at a lower altitude, at 3400 m, and after reaching maximal altitudes of 5600-6100 m). aMT6s excretion during the daytime remained unchanged during exposure to high altitudes. As expected, nocturnal values were higher than diurnal values at each point in time. However, there was a significant increase in nocturnal MLT excretion after the ascent to high altitudes. Ascent to high altitudes is associated with increased nocturnal excretion of aMT6s. The mechanism and physiological significance of this MLT increase are unclear.
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Base de dados:
MEDLINE
Assunto principal:
Altitude
/
Melatonina
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Áustria