Effect of vitamin A on rat hepatic mixed-function oxidases, glutathione transferase activity and generations of oxygen radicals.
Rat hepatic microsomal mixed-function oxidase activities were not significantly affected by vitamin A deficiency. Similarly cytosolic glutathione S-transferase and glutathione reductase activities as well as total glutathione levels were unaffected by the vitamin A status. Induction of the mixed-function oxidases by 3-methylcholanthrene or phenobarbitone was independent of the vitamin A status. No significant differences in microsomal chemiluminescence, before and following challenge with tertiary butyl hydroperoxide, were evident between the vitamin-A-deficient animals and those maintained on vitamin-A-supplemented diets. The present findings indicate that the protective action of vitamin A against chemical carcinogens is unlikely to involve modulation of the enzyme systems responsible for their metabolism.
Ayalogu
E O
EO
Biochemistry Department, University of Surrey, Guildford, UK.
Phillipson
C E
CE
Preece
N
N
Ioannides
C
C
Parke
D V
DV
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005609:Free Radicals; D005982:Glutathione Transferase / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014802:Vitamin A Deficiency / Q000201:enzymology*
D005609:Free Radicals; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D005982:Glutathione Transferase; D010100:Oxygen