Human nocturnal blood melatonin and liver acetylation status

The human dark phase melatonin concentrations exhibit a wide range of values. In an attempt to explain this variation, we measured 2250-2305 h melatonin levels by radioimmune assay in eleven fast and eleven slow acetylator phenotypes. No statistical difference between the two groups existed, suggesting therefore that such variations are not due to acetylator status. The study revealed a negative relationship between body weight or area and nocturnal melatonin concentration. No correlation was found between dark phase melatonin levels and age, anxiety, depression, or sleep rating.