Pineal function during aging: attenuation of the melatonin rhythm and its neurobiological consequences

The pineal hormone melatonin is a potent free radical scavenger. In particular, it quenches what is generally considered the most toxic and damaging free radical produced in the organism, the hydroxyl radical (.OH). Melatonin production in the pineal gland declines progressively with age such that in old animals and elderly humans the levels of melatonin available to the organism are a fraction of that of young individuals. A prominent theory of aging claims that the anatomical and functional degeneration that organs undergo during aging is a consequence of accumulated free radical damage. This being so, melatonin may well play a significant role in aging processes. If the drop in melatonin which normally occurs as animals age could be prevented, perhaps the aging process would also be delayed. Also, supplemental administration of melatonin may be beneficial in delaying age-related degenerative conditions. Certainly, free radical damage has been implicated in a number of neurodegenerative disorders. Theoretically, melatonin administration may forestall these as well.