Abstract
Effects of lyophilization and storage of liver 9, 000 × g supernatant fraction on the activity of drug metabolizing enzymes in some species of animals were studied. Imipramine metabolizing enzyme activity and the content of cytochrome P-450 were stable for, at least, one month without any loss of the activity when lyophilized liver 9, 000×g supernatant fraction of some animal species, i.e., rat, mouse, guinea pig, rabbit and dog, was stored under reduced pressure in a deep freezer (-20°C). There were no differences of imipramine metabolism between lyophilized liver 9, 000 × g supernatant fraction which was kept in a deep freezer for one month and a fresh fraction which was prepared immediately before determinations of the enzyme activity and cytochrome P-450. The data presented here indicated that the lyophilized preparation of the liver 9, 000 × g supernatant as well as the fresh preparation can be used for the determination of the drug metabolizing enzyme activity.
