AGING SELECTIVELY ALTERS GLUTATHIONE S-TRANSFERASE ISOZYME CONCENTRATIONS IN LIVER AND LUNG CYTOSOL

  • 1 January 1984
    • journal article
    • research article
    • Vol. 12  (5) , 661-671
Abstract
The effects of aging on hepatic and pulmonary cytosolic glutathione S-transferase activities and concentrations were investigated in male Fischer 344 rats, 3, 12 and 24 mo. old. Column isoelectric focusing of liver cytosol indicated that activities, measured with 6 epoxide substrates, of isozymes E, C and B increased from 3 to 12 mo. of age and decreased from 3 to 24 mo. of age whereas activities of isozyme A were increased in the old group. With lung cytosol, activities of isozymes E, C and B were decreased whereas isozyme A activities were increased in the old group. Purification to homogeneity of individual isozymes from liver and lung cytosol from each age group indicated that catalytic properties of isozymes were not altered by aging. Immunotitrations of hepatic and pulmonary cytosol from each age group showed that changes in the concentrations of these isoenzymes occurred with aging; hepatic isozymes E, C, and B increased from 3 to 12 mo. of age and then decreased by 24 mo. of age, whereas isozymes A and AA were increased by 24 mo. of age. Pulmonary isozymes E, C and B followed pattern of decline from 3 to 24 mo. of age, whereas isozyme A concentrations were unchanged with increasing age. Analysis of these changes suggested that subunits Ya and Yc as one group and Yb and Y''b as another followed similar increases (from 3 to 12 mo.) and decreases (from 12 to 24 mo.) in the liver and that these subunits showed consistent decreases with age in the lung. [These isoenzymes may function to decrease the toxicity and carcinogenicity of a number of compounds.].