Mutagenicity studies on paracetamol in human volunteers. III. Cytokinesis block micronucleus method.

As paracetamol (PC) affected the frequency of chromosome aberrations and unscheduled DNA synthesis in human volunteers, the genotoxic effects of PC were studied in a group of 12 healthy volunteers (9 females; 3 males, aged 37.8 +/- 8.7 years) using the cytokinesis block micronucleus method in human peripheral lymphocytes. As a positive control a group of elderly people was used, 20 females and 10 males, aged 79.9 +/- 9.5 years. PC was administered orally 3 times in a dose of 1000 mg during 8 h. Blood samples were taken at intervals of 0, 24, 72 and 168 h after the first dose of PC. Cytochalasin B was added to the cultures 44 h after the beginning of the 72-h cultivation at a concentration of 3.0 micrograms/ml. The frequency of cells with micronuclei in the group of volunteers was not significantly increased after PC administration. Using the cytokinesis block micronucleus method, the frequency of micronuclei was stable and the interindividual variability was low. The application of the micronucleus technique in genetic monitoring, e.g., for the occupational exposure to mutagens, is questioned.