The relationship between age and cutaneous aryl hydrocarbon hydroxylase (AHH) activity

Aryl hydrocarbon hydroxylase (AHH), a component of the mixed-function oxygenase system, has been identified in liver and in many extrahepatic tissues, including the skin. In this study, the effect of ageing on cutaneous AHH activity in both male and female Wistar and Brown Norwegian rats of two age groups (average ages being 44 and 130 weeks) was assessed using benzo(alpha)pyrene as substrate and by measuring the formation of the fluorescent metabolite 3-hydroxybenzo(alpha)pyrene. Results show that cutaneous metabolism of polycyclic aromatic hydrocarbons does not change between young adulthood and senescence in either male or female rats. Sex-related differences did occur, however, and may be explained, partly, by the existence of different molecular forms of cyt-P450. In conclusion, age does not appear to be a major determinant of basal cutaneous AHH activity in rats.