Arch Hellen Med, 17(5), September-October 2000, 524-527
The pineal hormone with multiple actions
Department of Endocrinology, “Metaxa” Hospital, Pireaus, Greece
Melatonin is a hormone of low molecular weight which is secreted into the systemic circulation by the pineal gland. Melatonin, which is a methoxyindole, has multiple functions, some of which are only recently becoming understood. It is involved in the adaptation of the organism to the light-dark environmental cycle and in the regulation of biological rhythms and of neuroendocrine function. It has been shown to modulate anterior and posterior pituitary hormone secretion and is involved in the regulation of reproduction in animals and humans. Melatonin is a general antioxidant which acts on all cells of the organism by neutralizing free radicals. Melatonin is involved in the regulation of the immune system where it has been shown to counteract the negative effects of acute stress and to have an immunoenhancing action. Research data from a series of in vitro and in vivo studies show that melatonin is an oncostatic agent and may be involved in the protection of the organism from carcinogenesis. A therapeutic role may quickly be developed for melatonin as it is already used for the prevention and treatment of jet lag and as therapy for sleep disorders. It may also be used in the prevention of premature ageing and in the treatment of cancer along with other therapeutic agents.
Key words: Biological rhythms, Carcinogenesis, Immune system, Melatonin, Reproduction.