The effect of ultraviolet irradiation on the carcinogenic potency of certain hydrocarbons.

As the rcsults of pul~lishcd investigations on concurrent application of carcinogenic agents and irradiation with ultraviolet, visible and infrared light (2, 6-8, 10-19) differ considerably, wc have found it of in?.crcst to investigate the activity of different carcinogenic hydrocarbons after ultraviolet irradiation. Cook and Martin (~), Dufraisse and Gerard (9) and Vel|uz (20) have shown that ultraviolet irradiation of carcinogenic hydrocarbons causes the formation of oxides that have the character of peroxides. Methylcholanthrcne and 9, 10-dimethyl1,2-bcnzanthracene are more readily photo-oxidized than 1, 2, 5, 6-dibenzanthracene and 3,4-bcnzyprene. Cook and Martin (5) have shown that the photooxide of 9,10-dimethyl-l,2-benzanthracene is noncarcinogenic in mice. Boyland and Boyland (4) found that the alkali-soluble product of 1,2,5,6-dibenzanthraccne after ultraviolet irradiation was noncarcinogenic in mice whereas Allsopp (1) found ~hat the alkali-soluble product of 3,4-bcnzpyrenc after ultraviolet irradiation was carcinogenic in mice.