Age related changes in NADPH cytochrome c reductase activity in mouse skin and liver microsomes

In this study, the effect of ageing on the activity of cutaneous and hepatic NADPH cytochrome c reductase, a component of the mixed function mono-oxygenase system, was studied in young adult and senescent male C57B1/6J mice. Horse heart cytochrome c was used as substrate and its reduction by skin and liver microsomes was measured spectrophotometrically. Statistical analysis of our results show a significant decrease in cutaneous enzyme activity with age. This, however, was not the case in liver where no significant difference was seen, consistent with previous studies on mixed function mono-oxygenase activity in mouse liver. This suggests that the ageing process may have a tissue specific effect on the monooxygenase system in the C57B1/6J strain of mouse. However, further work in other rodent species and humans is required to fully characterize the effect of ageing on the drug metabolizing capacity of skin as compared to liver.