Young male CBA/LacStoRap mice were exposed for two hours to volatile components of native or dialyzed urine (VC or VCd, respectively) of mature males of the same line. To estimate the effects of VC and VCd on bone marrow cells, cytogenetic analysis of mitotic disturbances in anaphase-telophase cells was performed. The overall frequency of mitotic disturbances in VC-treated mice became significantly higher 24 and 48 h after exposure but returned to the initial level 72 h after exposure (P