Tissue-specific differential induction of ornithine aminotransferase by estradiol in rats of various ages

Abstract

The level and induction of ornithine aminotransferase of the liver and kidney cortex were determined at different phases of the life span of female rats. The level of this enzyme in the liver did not change significantly till adulthood and decreased thereafter. However, there was no significant differences in the level of this enzyme in the kidney cortex of the rat throughout its life span. Further, the level of this enzyme in the kidney cortex was more than 2.5-fold higher than that of the liver in all the age groups. Ovariectomy decreased, and 17-beta-estradiol increased significantly, the activity of the kidney cortex enzyme in rats except for the old ones. The effects of both these treatments were highest in the young-adult (13-weeks) rats. In contrast, the liver enzyme was irresponsive towards both these treatments.