Tags

Type your tag names separated by a space and hit enter

Melatonin in relation to cellular antioxidative defense mechanisms.
Horm Metab Res. 1997 Aug; 29(8):363-72.HM

Abstract

Melatonin's actions in organisms are more widespread than originally envisaged. Over three decades ago, the changing pattern of nocturnal melatonin production was found to be the signal for the annual cycle of reproduction in photoperiodic species. Since then, melatonin's actions also have been linked to circadian rhythms, immune function, sleep, retinal physiology and endocrine functions in general. In recent years, however, the sphere of influence of melatonin was further expanded when the indole was found to be an effective free radical scavenger and antioxidant. Free radicals are toxic molecules, many being derived from oxygen, which are persistently produced and incessantly attack and damage molecules within cells; most frequently this damage is measured as peroxidized lipid products, carbonyl proteins, and DNA breakage or fragmentation. Collectively, the process of free radical damage to molecules is referred to as oxidative stress. Melatonin reduces oxidative stress by several means. Thus, the indole is an effective scavenger of both the highly toxic hydroxyl radical, produced by the 3 electron reduction of oxygen, and the peroxyl radical, which is generated during the oxidation of unsaturated lipids and which is sufficiently toxic to propagate lipid peroxidation. Additionally, melatonin may stimulate some important antioxidative enzymes, i.e., superoxide dismutase, glutathione peroxidase and glutathione reductase. In in vivo tests, melatonin in pharmacological doses has been found effective in reducing macromolecular damage that is a consequence of a variety of toxic agents, xenobiotics and experimental paradigms which induce free radical generation. In these studies, melatonin was found to significantly inhibit oxidative damage that is a consequence of paraquat toxicity, potassium cyanide administration, lipopolysaccharide treatment, kainic acid injection, carcinogen administration, carbon tetrachloride poisoning, etc., as well as reducing the oxidation of macromolecules that occurs during strenuous exercise or ischemia-reperfusion. In experimental models which are used to study neurodegenerative changes associated with Alzheimer's and Parkinson disease, melatonin was found to be effective in reducing neuronal damage. Its lack of toxicity and the ease with which melatonin crosses morphophysiological barriers and enters subcellular compartments are essential features of this antioxidant. Thus far, most frequently pharmacological levels of melatonin have been used to combat oxygen toxicity. The role of physiological levels of melatonin, which are known to decrease with age, is being investigated as to their importance in the total antioxidative defense capacity of the organism.

Authors+Show Affiliations

Department of Cellular and Structural Biology, University of Texas Health Science Center, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

9288572

Citation

Reiter, R J., et al. "Melatonin in Relation to Cellular Antioxidative Defense Mechanisms." Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme, vol. 29, no. 8, 1997, pp. 363-72.
Reiter RJ, Carneiro RC, Oh CS. Melatonin in relation to cellular antioxidative defense mechanisms. Horm Metab Res. 1997;29(8):363-72.
Reiter, R. J., Carneiro, R. C., & Oh, C. S. (1997). Melatonin in relation to cellular antioxidative defense mechanisms. Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme, 29(8), 363-72.
Reiter RJ, Carneiro RC, Oh CS. Melatonin in Relation to Cellular Antioxidative Defense Mechanisms. Horm Metab Res. 1997;29(8):363-72. PubMed PMID: 9288572.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Melatonin in relation to cellular antioxidative defense mechanisms. AU - Reiter,R J, AU - Carneiro,R C, AU - Oh,C S, PY - 1997/8/1/pubmed PY - 1997/8/1/medline PY - 1997/8/1/entrez SP - 363 EP - 72 JF - Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme JO - Horm Metab Res VL - 29 IS - 8 N2 - Melatonin's actions in organisms are more widespread than originally envisaged. Over three decades ago, the changing pattern of nocturnal melatonin production was found to be the signal for the annual cycle of reproduction in photoperiodic species. Since then, melatonin's actions also have been linked to circadian rhythms, immune function, sleep, retinal physiology and endocrine functions in general. In recent years, however, the sphere of influence of melatonin was further expanded when the indole was found to be an effective free radical scavenger and antioxidant. Free radicals are toxic molecules, many being derived from oxygen, which are persistently produced and incessantly attack and damage molecules within cells; most frequently this damage is measured as peroxidized lipid products, carbonyl proteins, and DNA breakage or fragmentation. Collectively, the process of free radical damage to molecules is referred to as oxidative stress. Melatonin reduces oxidative stress by several means. Thus, the indole is an effective scavenger of both the highly toxic hydroxyl radical, produced by the 3 electron reduction of oxygen, and the peroxyl radical, which is generated during the oxidation of unsaturated lipids and which is sufficiently toxic to propagate lipid peroxidation. Additionally, melatonin may stimulate some important antioxidative enzymes, i.e., superoxide dismutase, glutathione peroxidase and glutathione reductase. In in vivo tests, melatonin in pharmacological doses has been found effective in reducing macromolecular damage that is a consequence of a variety of toxic agents, xenobiotics and experimental paradigms which induce free radical generation. In these studies, melatonin was found to significantly inhibit oxidative damage that is a consequence of paraquat toxicity, potassium cyanide administration, lipopolysaccharide treatment, kainic acid injection, carcinogen administration, carbon tetrachloride poisoning, etc., as well as reducing the oxidation of macromolecules that occurs during strenuous exercise or ischemia-reperfusion. In experimental models which are used to study neurodegenerative changes associated with Alzheimer's and Parkinson disease, melatonin was found to be effective in reducing neuronal damage. Its lack of toxicity and the ease with which melatonin crosses morphophysiological barriers and enters subcellular compartments are essential features of this antioxidant. Thus far, most frequently pharmacological levels of melatonin have been used to combat oxygen toxicity. The role of physiological levels of melatonin, which are known to decrease with age, is being investigated as to their importance in the total antioxidative defense capacity of the organism. SN - 0018-5043 UR - https://www.unboundmedicine.com/medline/citation/9288572/Melatonin_in_relation_to_cellular_antioxidative_defense_mechanisms_ L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-2007-979057 DB - PRIME DP - Unbound Medicine ER -