Melanins in physiological conditions protect against lipoperoxidation. A study on albino and pigmented Xenopus.
The susceptibility to lipoperoxidation in liver of albino and pigmented Xenopus laevis Daudin, has been studied. Albino Xenopus liver was richer in polyunsaturated fatty acids (PUFAs) than the pigmented one; moreover, it was also richer in mitochondrial superoxide dismutase (MnSOD) and in reduced glutathione (GSH). The thiobarbituric acid-reactive substances (TBARS) values were more abundant in the albino tissue compared to the pigmented tissue both during spontaneous and Fe++ induced lipoperoxidation. Therefore, when isolated and purified melanin, in physiological quantities, was added to albino tissue, the TBARS values drastically decreased. Thus, melanin, in our experimental conditions, protects the albino tissue even more than SOD and GSH do. Melanin, in our opinion, acts as an antioxidant, because it is able to scavenge O2-.
Corsaro
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C
Institute of "Biologia generale," University of Catania, Italy.
Scalia
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M
Blanco
A R
AR
Aiello
I
I
Sichel
G
G
D000417:Albinism; D000818:Animals; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D005296:Ferrous Compounds / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000378:metabolism*; D008297:Male; D008543:Melanins / Q000494:pharmacology / Q000502:physiology*; D008930:Mitochondria, Liver / Q000201:enzymology; D010858:Pigmentation; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014982:Xenopus laevis
D005231:Fatty Acids, Unsaturated; D005296:Ferrous Compounds; D008543:Melanins; D017392:Thiobarbituric Acid Reactive Substances; D013482:Superoxide Dismutase; D005978:Glutathione