Effect of age on the induction of in vitro drug metabolism by pregnenolone-16 alpha-carbonitrile (PCN); effect of age and PCN on immune responses.

The drug metabolizing capacity and the immune responses of normal and PCN treated young, adult and old rats were studied. In normal young and old rats the drug metabolism in general and the immune responses were reduced in comparison to adult animals. PCN treatment caused significant increase of drug metabolism in all age groups of animals due to induction of the microsomal enzymes of the liver. However, there were certain drug dependant variations in the different age groups of rats. PCN given in vivo affected differently the responses of T and B-cells in the young, adult and old animals. PCN is a non-hormonal microsomal enzyme inducer and the question a-rises as to whether there is any connection between this process and the immune system.