RESUMO
In order to examine the influence of the length of cell cycle on the incidence of sister chromatid exchanges (SCEs), average generation times and SCEs were studied in the presence of bromodeoxyuridine from spontaneously dividing rat lymph node, bone marrow, spleen, and spermatogonial cells. Average generation time differences among the three somatic cell types (lymph node, 7.6 h; bone marrow, 12.0 h; spleen, 14.9 h) were statistically significant as were the differences between the germinal cell (37.4 h) and each of the somatic cells. The SCE per cell frequencies were significantly higher in the somatic cells (lymph node, 6.8; bone marrow, 5.8; spleen, 6.1) as compared to the spermatogonial cells (1.6). However, no difference in SCE incidence was detected among the cells from the different somatic tissues. It was concluded that there was no simple relationship between cell cycle duration time and SCE formation.
