Hormones: Melatonin
Melatonin is mainly produced by the pineal gland and, although it appears not to be essential for human physiology, it is known to have a range of different effects when taken as a medication. Function of melatonin in the brain Melatonin (blue) is produced naturally by the pineal gland (purple) at night-time indicated by light entering the eyes (left), and by the arrow showing the melatonin secretion signal sent by the optic nerve to the pineal gland once darkness has fallen. Alternative names for melatonin N-acetyl-5-methoxytryptamine. What is melatonin? Melatonin is produced by various tissues in the body, although the major source is the pineal gland in the brain. The production and release of melatonin from the pineal gland occurs with a clear daily (circadian) rhythm, with peak levels occurring at night. Melatonin is carried by the circulation from the brain to all areas of the body. Tissues expressing proteins called receptors specific for melatonin are able to d...