RESUMEN
Experiments have been carried out on liver and Kidneys to study the age dependent changes in alanine and aspartate aminotransferases and the influence of steroid hormones corticosterone (catabolic), testosterone (anabolic) and vitamin B6 on these changes. The rats used were of the ages between 7 to 73 weeks. It is observed that specific activity of alanine aminotransferase as well as the activity per liver increased with age. The same is true with the kidneys. Corticosterone treatment brings about two and half fold increase in activity in the liver of younger rats, whereas there is only 25% increase in the oldest group. Testosterone and vitamin B6 lower this activity, the latter showed more pronounced effect. In the case of kidneys the changes are marginal. Aspartate aminotransferase shows marginal changes in the specific activities in both liver and kidney, whereas the total activity increases with age, except in the case of liver where there is decrease at 73 weeks. Both testosterone and vitamin B6 have marginal influence on the kidney enzyme. There is no apparent explanation for the differential behaviour of the two enzymes.