UDS induction by an array of standard carcinogens in human and rodent hepatocytes: effect of cryopreservation

The UDS induction assay with primary hepatocytes as the target cells is a d eterminative assay for chemical carcinogens. This assay is, however, limite d to the availability of freshly prepared liver cells. A cryopreservation t echnique for liver cells has recently been described. Frozen cells have bee n shown to retain a variety of enzyme activities essential for xenobiotic m etabolism after being thawed. In the present investigation, 19 direct or in direct-acting carcinogens were tested with respect to their capacity to ind uce DNA repair in primary as well as cryopreserved human and rat hepatocyte s. Cryopreserved cells yielded results that were essentially indistinguisha ble from fresh cells. Only marginal differences were observed between hepat ocytes of rat or human origin. These results demonstrate the suitability of cryopreserved hepatocytes as indicator cells for the study of UDS inductio n to discover possible carcinogenecity in chemicals. (C) 2000 Elsevier Scie nce Ireland Ltd. All rights reserved.