Human exposures to mutagens--an analysis using the genetic activity profile database.

The Genetic Activity Profile (GAP) database was used to identify and compare agents showing genotoxic activity in humans. The database revealed several substances for which both human and rodent cytogenetic data existed. Based on the ratio of the lowest effective doses (LEDs) in rodents versus human studies, humans appear to be at least 10 times more sensitive than rodents to the majority of the genotoxic substances examined. Several caveats are discussed which may be responsible, in part, for the apparent differences in sensitivity. Some of these differences could be due to variations in the test protocols or they may, in fact, reflect real differences between human and rodent cells. However, in contrast to the in vivo comparison, the LEDs for human data from in vitro studies were not uniformly lower than for comparable studies in rodents. The in vitro comparison suggests that the apparent differences in human versus rodent cell sensitivity seen in vivo must be viewed with a degree of caution. Nevertheless, the overall GAPs for these agents, and particularly the human in vivo data, underscore the concern for adequate protection of humans exposed to these environmental mutagens.