Interactions of the pineal hormone melatonin with oxygen-centered free radicals: a brief review
- PMID: 8136717
Interactions of the pineal hormone melatonin with oxygen-centered free radicals: a brief review
Abstract
Melatonin,N-acetyl-5-methoxytryptamine, is a hormonal product of the pineal gland. Its synthesis is higher at night than during the day in all vertebrates including man. Once melatonin is produced in the pineal gland it is quickly released into the vascular system. The rapid release of melatonin is generally believed to relate to its high lipophilicity which allows it to readily pass through the membrane of the pinealocytes and the endothelial cells which line the capillaries. The result of the nocturnal synthesis and secretion of melatonin is high blood levels at night. Also because of its highly lipophilic nature, melatonin from the blood readily escapes into every other bodily fluid and all cells in the body. Until recently it was generally thought that melatonin's action in the organism depended on its exclusive interaction with specific receptors on cells located in discrete locations. Certainly, the interactions of melatonin with these membrane-bound receptors are believed to mediate the endocrine and circadian rhythm effects of melatonin. It was recently discovered, however, that melatonin's primary action may not depend on the previously described membrane receptors. We have found that melatonin is a very potent hydroxyl radical scavenger; free radicals and the hydroxyl radical in particular, because of its very high reactivity, can be extremely damaging to macromolecules in cells. Compared to glutathione and mannitol, two well known free radical scavengers, melatonin is a more powerful scavenger and affords protection of molecules, especially DNA, from oxidative damage. Melatonin's extremely high diffusibility is important for its scavenging action because this feature allows it to enter all cells and every subcellular compartment. Whereas the free radical quenching activity of melatonin does not require a receptor, we also have evidence that it may be bound in the nucleus thereby providing on-site protection to DNA. Besides scavenging the highly toxic hydroxyl radical, melatonin also stimulates glutathione peroxidase activity which metabolizes the precursor of the hydroxyl radical, hydrogen peroxide, to water. Thus, melatonin has at least two means to protect the cell from oxidative damage, i.e., it breaks down hydrogen peroxide to harmless water and, in the event any hydroxyl radicals are formed, melatonin scavenges them. Melatonin may be the premier molecule to protect the organism from oxidative damage.
Similar articles
-
Functional pleiotropy of the neurohormone melatonin: antioxidant protection and neuroendocrine regulation.Front Neuroendocrinol. 1995 Oct;16(4):383-415. doi: 10.1006/frne.1995.1014. Front Neuroendocrinol. 1995. PMID: 8557171 Review.
-
A review of the evidence supporting melatonin's role as an antioxidant.J Pineal Res. 1995 Jan;18(1):1-11. doi: 10.1111/j.1600-079x.1995.tb00133.x. J Pineal Res. 1995. PMID: 7776173 Review.
-
Melatonin in relation to cellular antioxidative defense mechanisms.Horm Metab Res. 1997 Aug;29(8):363-72. doi: 10.1055/s-2007-979057. Horm Metab Res. 1997. PMID: 9288572 Review.
-
Pineal function during aging: attenuation of the melatonin rhythm and its neurobiological consequences.Acta Neurobiol Exp (Wars). 1994;54 Suppl:31-9. Acta Neurobiol Exp (Wars). 1994. PMID: 7801790 Review.
-
Suppression of oxygen toxicity by melatonin.Zhongguo Yao Li Xue Bao. 1998 Nov;19(6):575-81. Zhongguo Yao Li Xue Bao. 1998. PMID: 10437151 Review.
Cited by
-
Potency of melatonin in living beings.Dev Reprod. 2013 Sep;17(3):149-77. doi: 10.12717/DR.2013.17.3.149. Dev Reprod. 2013. PMID: 25949131 Free PMC article.
-
Melatonin regulates the ovarian function and enhances follicle growth in aging laying hens via activating the mammalian target of rapamycin pathway.Poult Sci. 2020 Apr;99(4):2185-2195. doi: 10.1016/j.psj.2019.11.040. Epub 2020 Jan 29. Poult Sci. 2020. PMID: 32241504 Free PMC article.
-
Role of Melatonin in Periodontal Diseases: A Structured Review.Adv Biomed Res. 2024 Sep 23;13:88. doi: 10.4103/abr.abr_152_23. eCollection 2024. Adv Biomed Res. 2024. PMID: 39512417 Free PMC article. Review.
-
Does melatonin protect or treat brain damage from traumatic oxidative stress?Exp Brain Res. 2005 Jun;163(3):406-10. doi: 10.1007/s00221-005-2338-2. Epub 2005 Apr 27. Exp Brain Res. 2005. PMID: 15856200
-
Effects of N-acetyl cysteine and melatonin on early reperfusion injury in patients undergoing coronary artery bypass grafting: A randomized, open-labeled, placebo-controlled trial.Medicine (Baltimore). 2018 Jul;97(30):e11383. doi: 10.1097/MD.0000000000011383. Medicine (Baltimore). 2018. PMID: 30045259 Free PMC article. Clinical Trial.
Publication types
MeSH terms
Substances
LinkOut - more resources
Other Literature Sources