抄録
Prioritized assessment chemicals will be evaluated for their risks, and then, they will be designated to the second specific chemicals in the amended Kashin-law from April 2011. In the genotoxic risk evaluation, in vivo test data will be needed if in vitro test showed positive. However, there is no consensus on what case or which test should be requested. Therefore, prioritization of request of in vivo micronucleus assay (MN) data was investigated in case of positive for in vitro chromosomal aberration test (CA). There are 66 chemicals which are positive for in vitro CA tests with Ames and MN data among 277 existing chemicals in Kashin-law database. Lowest effective concentration (LEC) in the CA data and results of Ames and MN test were compared. There were tendencies that Ames-positive chemicals show MN-positive regardless of LEC value and CA-positive chemicals with low LEC show MN-positive even if Ames-negative. Following criterion values are set for LEC: 1) ≤ 0.05 mg/mL, 2) 0.05-0.5 mg/mL, and 3) > 0.5 mg/mL. MN-positives (Ames-negatives, within) and Ames-positives are 8 (3), 6 among 19 chemicals in LEC 1), respectively, and are 1 (0), 4 among 21 chemicals in LEC 2), and 3 (1), 7 among 26 chemicals in LEC 3). These results indicate that priorities of request of in vivo MN data are high, middle, and low in LEC 1), 2) and 3), respectively. Ames-positives are also high priority. This approach will be effective in risk communication for the request of MN data under the Kashin-law.
