Clastogenic effect of BrdU on different phases of human lymphocyte "in vitro" cell cycle.

From the data presented, it can be pointed out a mitotic delay in the cell cycle, possibly due to BrdU cytotoxic effect. Irradiation in G1 phase does not produce any increase in SCE frequency while irradiation in S or G2 phase increases significantly this frequency. Our data support the hypothesis that BrdU does not produce by itself an increase of chromosome aberrations but act as sensitizer for cells which have incorporated it.