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DNA adduct formation by mineral oils and their fractions as indicated by 32 P‐postlabelling: Is adduct formation truly indicative of carcinogenic potential?
Author(s) -
Ingram A. J.,
Phillips J. C.,
Lee R.
Publication year - 1995
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.2550150408
Subject(s) - carcinogen , adduct , chemistry , fraction (chemistry) , dna adduct , ring (chemistry) , organic chemistry
Oils of differing types, physical properties and carcinogenic activity were tested for their ability to produce epidermal DNA adducts 24 h after application to the skin of mice, using the 32 P‐postlabelling method. Two studies were carried out, the first on three oils to identify the adduct‐forming components, and the second on nine oils to investigate whether the nature of the oils affected their adduct‐forming potential. In addition to the whole oils, fractions of the oils containing saturated hydrocarbons, 2–6‐ring aromatic compounds and polar compounds were tested in both studies in proportion to their concentration in the original oil. In addition, a further examination of the aromatic fractions from two carcinogenic oils was carried out in the first study by testing 2–3‐ring and 4–6‐ring subfractions (the latter containing carcinogenic polycyclic aromatic compounds (PACs)). Results from the first study indicated that carcinogenic oils do produce adducts and that the adduct‐forming components were mainly in the aromatic fraction. When, however, subfractions of the aromatic fraction were examined, it was found that slightly higher adduct levels were produced by the 2–3‐ring aromatic fraction than with the 4–6‐ring PAC fraction. This was contrary to expectation from published work on the skin carcinogenicity of oils and suggested that some non‐carcinogenic PACs may produce adducts. The second study indicated that although most carcinogenic oils produced adducts, some non‐carcinogenic oils can also do so. This was especially evident with a non‐carcinogenic residual oil and, as such oils have been reported to contain high levels of 2–3‐ring PACs, this was taken as further evidence that some non‐carcinogenic PACs containing three or four aromatic rings may give rise to DNA adducts. Further studies are needed to confirm whether or not non‐carcinogenic components of oils are indeed able to produce adducts.