Variation of urinary melatonin excretion in humans during the first 30 years of life.

Urinary melatonin variation in humans were demonstrated to be a function of age. A radioimmunological assay was used. The values obtained, expressed as nmol x 24 h-1 x kg-1, progressively decreased from birth onwards, with a more accentuated and momentary inflection at the moment of the genital crisis in newborns and at puberty. The results obtained concern only melatonin and not its metabolites, as a result of the high specificity of the antibodies employed.