Simultaneous assessment of ethyl carbamate-induced SCEs in murine lymphocytes, bone marrow and alveolar macrophage cells.

At 3, 6, and 24 h after acute treatment of BD2F1 mice with 3.3 mmol/kg of ethyl carbamate, blood was drawn and cultured for SCE analysis. After blood sampling, the same mice were infused with BrdUrd for simultaneous assessment of SCEs in bone marrow and alveolar macrophage cells. In bone marrow and alveolar macrophage cells, maximum SCE responses (24.1 +/- 4.3; 24.2 +/- 3.8, respectively) were observed at 3 h post-exposure. Decreased SCE frequencies were observed at each later time. Relative to a single (3.3 mmol/kg) acute treatment, multiple treatment (10 X 3.3 mmol/kg; every other day) did not produce significantly elevated SCE levels in bone marrow (18.3 +/- 1.5) and alveolar macrophage cells (22.2 +/- 5.8). By contrast, the maximum lymphocyte response (18.8 +/- 2.2), following a single acute injection, was observed at 6 h post-exposure. In addition, a considerable accumulation of SCE frequencies occurred in lymphocytes (27.3 +/- 3.4) following multiple injections of ethyl carbamate.