Content of liver and brain ubiquinol-9 and ubiquinol-10 after chronic ethanol intake in rats subjected to two levels of dietary alpha-tocopherol.
To assess the effect of chronic ethanol ingestion in the content of the reduced forms of coenzymes Q9 (ubiquinol-9) and Q10 (ubiquinol-10) as a factor contributing to oxidative stress in liver and brain, male Wistar rats were fed ad libitum a basal diet containing either 10 or 2.5 mg alpha-tocopherol/100 g diet (controls), or the same basal diet plus a 32% ethanol-25% sucrose solution. After three months treatment, ethanol chronically-treated rats showed identical growth rates to the isocalorically pair-fed controls, irrespectively of alpha-tocopherol dietary level. Lowering dietary alpha-tocopherol led to a decreased content of this vitamin in the liver and brain of control rats, without changes in that of ubiquinol-9, and increased levels of hepatic ubiquinol-10 and total glutathione (tGSH), accompanied by a decrease in brain tGSH. At the two levels of dietary alpha-tocopherol, ethanol treatment significantly decreased the content of hepatic alpha-tocopherol and ubiquinols 9 and 10. This effect was significantly greater at 10 mg alpha-tocopherol/100 g diet than at 2.5, whereas those of tGSH were significantly elevated by 43% and 9%, respectively. Chronic ethanol intake did not alter the content of brain alpha-tocopherol and tGSH, whereas those of ubiquinol-9 were significantly lowered by 20% and 14% in rats subjected to 10 and 2.5 mg alpha-tocopherol/100 g diet, respectively. It is concluded that chronic ethanol intake at two levels of dietary alpha-tocopherol induces a depletion of hepatic alpha-tocopherol and ubiquinols 9 and 10, thus contributing to ethanol-induced oxidative stress in the liver tissue. This effect of ethanol is dependent upon the dietary level of alpha-tocopherol, involves a compensatory enhancement in hepatic tGSH availability, and is not observed in the brain tissue, probably due to its limited capacity for ethanol biotransformation and glutathione synthesis.
Junqueira
V B
VB
Departamento de Medicina, Universidade Federal de São Paulo, Brasil. junqueira-geriat@pesquisa.epm.br
Carrasquedo
F
F
Azzalis
L A
LA
Giavarotti
K A
KA
Giavarotti
L
L
Rodrigues
L
L
Fraga
C G
CG
Boveris
A
A
Videla
L A
LA
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D004032:Diet; D000431:Ethanol / Q000008:administration & dosage*; D005978:Glutathione / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000378:metabolism*; D014810:Vitamin E / Q000008:administration & dosage*
D014451:Ubiquinone; D014810:Vitamin E; D000431:Ethanol; C026663:ubiquinol-10; D005978:Glutathione; C003741:ubiquinol