The effect of vitamin A deficiency on hepatic, renal and pulmonary glutathione S-transferase activities in the rat.
Feeding male weanling rats on a vitamin A-deficient diet for 6 weeks resulted in significant increases (44-57%) in glutathione S-aryl-, S-aralkyl- S-alkyl- and S-epoxidetransferase activities in the liver cytosol. Only the S-aralkyl- (27%) and S-alkyltransferase (14%) activities were significantly increased in the kidney as a result of deficiency. There was no effect on any of the pulmonary glutathione S-transferase activities. The increases in hepatic transferase activities were due primarily to increases (25-96%) in the apparent Vmax. There were no changes in the apparant Km of any of the four drug substrates employed. With 3,4-dichloronitrobenzene as the second substrate, the apparent Km for glutathione was increased by over 2-fold in vitamin A-deficient livers as compared with controls. The relationship between these results and enhanced susceptibility to chemical carcinogens in vitamin A deficiency is briefly discussed, and comparison is made between the effects of this nutritional state and pretreatment with drug inducers on the glutathione S-transferases.
D000818:Animals; D003600:Cytosol / Q000201:enzymology; D005982:Glutathione Transferase / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008168:Lung / Q000201:enzymology*; D008297:Male; D051381:Rats; D013379:Substrate Specificity; D014802:Vitamin A Deficiency / Q000201:enzymology*
D005982:Glutathione Transferase