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Additional information

Three in vitro bacterial reverse mutation assays (Ames tests) were performed with the test substance 2 -vinylpyridine following a test method equivalent or similar to OECD Guideline 471. In the first study, Salmonella strains TA 100 and TA 1535 gave positive results in the presence of exogenous metabolic activation, while S. typhimurium gave ambiguous results. Slightly toxicity was found at concentrations of 5000 µg/plate and above. In the second study, Salmonella typhimurium strains TA 100, TA 1535 and TA 98 were exposed to the test substance, with and without metabolic activation. 2 -vinylpyridine did not induce a significant increase in revertant colonies both in the presence and in the absence of metabolic activation. Negative results for genotoxicity were also reported in the third study, in wich Salmonella typhimurium strains TA 1535, TA 1538, TA 98 and TA 100 were exposed to 2 -vinylpyridine in the absence and in the presence of a metabolic activation system (S9 liver fraction of rats pretreated with Aroclor).

2 -vinylpyridine was also assayed for genotoxicity by means of the rat hepatocyte DNA-repair test: primary rat liver cells were exposed to the test substance and the genotoxicity was evaluated by means of counting the radiolabeled thymidine uptake by the cells.

The test substance was found to be toxic at the three highest doses. No genotoxicity was observed at non-toxic doses (2.5 mmol). Thus, 2-vinylpyridine was concluded to be non-genotoxic to primary rat hepatocytes when assayed at non-toxic doses.

In the last study, Chinese hamster ovary (CHO) cells were exposed to 2 -vinylpyridine concentrations over a period of 24 hours in order to evaluate the cytotoxic effects of the test substance. 2 -vinylpyridine was found to increase cytotoxicity under test conditions. It was suggested that the increased toxicity of vinylpyridines may be due to the reactivity of the vinyl group to cellular proteins and DNA.

Although 2 -vinylpyridine exhibited positive evidence of mutagenicity under in-vitro conditions in some Salmonella typhimurium strains, taking into account all the available genotoxicity information on 2 -vinylpyridine for the weight of evidence analysis, it is concluded that the substance cannot be regarded as genotoxic.

Short description of key information:
Weight of evidence approach based on in vitro bacterial reverse mutation assays, a DNA damage and repair assay and a cytotoxicity assay in CHO cells with 2-vinylpyridine.

Endpoint Conclusion:

Justification for classification or non-classification

Only in vitro studies are available for 2 -vinylpyridine. There are no studies of exposed humans and no genotoxicity tests performed in vivo. Thus, it is concluded that there is no data available that would justify classification for germ cell mutagenicity according to CLP criteria.