BACKGROUND: Melatonin (MEL) production occurs mainly during the dark span. A prominent circadian variation is demonstrated in both blood and urine in humans. MATERIALS AND METHODS: The circadian, circannual, age and gender patterns of MEL were concomitantly investigated in 40 men and 132 women, each providing blood samples every 4 hours for 24 hours for conventional and cosinor analysis. RESULTS: Circulating MEL is circadian periodic (P < 0.001), peaking at night. The MESOR (rhythm-adjusted mean) is higher in women than in men. The circadian amplitude decreases with age. Both are modulated by a circannual variation, the MESOR peaking in winter (P < 0.001) and the circadian amplitude in summer (P < 0.05). CONCLUSIONS: Samples, unqualified as to gender, age and/or season, incompletely characterize the circadian MEL patterns. This chronome approach detects changes that may escape detection otherwise, checking whether a value is too high or too low, and also whether "swinging" occurs to the right extent.
BACKGROUND:Melatonin (MEL) production occurs mainly during the dark span. A prominent circadian variation is demonstrated in both blood and urine in humans. MATERIALS AND METHODS: The circadian, circannual, age and gender patterns of MEL were concomitantly investigated in 40 men and 132 women, each providing blood samples every 4 hours for 24 hours for conventional and cosinor analysis. RESULTS: Circulating MEL is circadian periodic (P < 0.001), peaking at night. The MESOR (rhythm-adjusted mean) is higher in women than in men. The circadian amplitude decreases with age. Both are modulated by a circannual variation, the MESOR peaking in winter (P < 0.001) and the circadian amplitude in summer (P < 0.05). CONCLUSIONS: Samples, unqualified as to gender, age and/or season, incompletely characterize the circadian MEL patterns. This chronome approach detects changes that may escape detection otherwise, checking whether a value is too high or too low, and also whether "swinging" occurs to the right extent.
Authors: A Olah; R Jozsa; V Csernus; J Sandor; A Muller; M Zeman; W Hoogerwerf; G Cornélissen; F Halberg Journal: Neurotox Res Date: 2008-04 Impact factor: 3.911
Authors: F Halberg; G Cornélissen; G Katinas; J Dušek; P Homolka; Z Karpíšek; R P P Sonkowsky; O Schwartzkopff; B Fišer; J Siegelová Journal: Scr Med (Brno) Date: 2007-10-01