RESUMO
We observe changes of activation of hepatic microsomal cytochrome p-450, changes of formation of riug-and N-hydroxylation of 2-acetylaminofluorene, and changes of vitamin D, in the liver which exposed to UV light and expoeed to UV light after being applied by sunscreens. The results of our study are as shown below: 1. The contents of hepatic microsomal cytochrome p-45p of newborn rats were found to be remarkably increase in the group exposed to UV light for 3 weeks (p<0. 001), but such changes were much reduced in the group exposed to UV light for 3 weeks after being applied by sunscreens(p<0.05. p<0.001, ) 2.Cytochrome p-450 induced by UV light was found to be significantly increased ring and N-hydroxylation of 2-acetylarninofluorene known as carcinogenic source for the liver. In the group exposed to UV light for 3 weeks after being applied by sunscreens, both of ring-and N-hydroxylation of 2-acetylaminofluorene were significantly reduced(p<0. 0, p<0. 001). 3, The contents of vitarnin D, in the liver of newborn rats were found to be gradually increased when they were exposed to UV light for 1 week or 3 weeks (p<0. 001), and in the group exposed to UV light after being applied by sunscreens, such changes were reduced remarkably(pg0. (301).