The circadian rhythm in plasma melatonin concentration of the urbanized man: the effect of summer and winter time.
Plasma melatonin rhythms were measured in healthy urbanized persons between July 4 and 5 and between January 13 and 14. In contrast to findings in other mammals studied thus far, no difference in the duration of elevated night melatonin concentration was observed between summer and winter. In winter, melatonin rhythms were phase-delayed by about 1.5 h as compared with summer patterns.
D000328:Adult; D002940:Circadian Rhythm; D006801:Humans; D008297:Male; D008550:Melatonin / Q000097:blood*; D008875:Middle Aged; D012621:Seasons; D014505:Urban Population
D008550:Melatonin