Ethanol inhibits melatonin secretion in healthy volunteers in a dose-dependent randomized double blind cross-over study.
To elucidate the effects of alcohol on pineal rhythmicity, ethanol was administered in the evening in amounts usually consumed during social ingestion to nine healthy volunteers in a double blind, cross-over study. Plasma concentrations of melatonin, catecholamines (norepinephrine and epinephrine), and ethanol were measured by RIA, high pressure liquid chromatography, and gas chromatography before and for 12 h after the administration of 0, 0.5, and 1 g ethanol/kg wt. Plasma melatonin and catecholamines displayed expected diurnal rhythms, with peak values at 0300-0400 h for melatonin and trough values at 0100-0400 h for catecholamines. Intake of ethanol between 1900-1945 h inhibited the nocturnal melatonin secretion dose-dependently during the first half of the night, with no changes in urinary excretion of melatonin. The inhibition was 41% (P < 0.05) from the control at midnight for both ethanol doses, 33% (P < 0.05) at 0100 h, and 18% (P < 0.05) at 0200 h for the higher dose. In addition, the higher dose of ethanol increased plasma norepinephrine levels at 2000 and 2200 h (P < 0.01) until 0400 h (P < 0.05). Taking into account the involvement of melatonin in the regulation of sleep and diurnal rhythms, we suggest that ethanol-induced suppression of nocturnal melatonin secretion and an increase in noradrenergic activity may be closely associated with disturbances in sleep and performance.
Ekman
A C
AC
Department of Physiology, University of Oulu, Finland.
Leppäluoto
J
J
Huttunen
P
P
Aranko
K
K
Vakkuri
O
O
D000328:Adult; D002940:Circadian Rhythm; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood; D000431:Ethanol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008550:Melatonin / Q000097:blood / Q000378:metabolism*; D009638:Norepinephrine / Q000097:blood; D011897:Random Allocation
D000431:Ethanol; D008550:Melatonin; D009638:Norepinephrine; D004837:Epinephrine