Effect of Diethylstilbestrol Diphosphate on Mitotic Activity in Bovine Lymphocyte Cultures

Abstract

The mitotic activity of bovine lymphocyte cultures was used as a measure of the cytotoxicity of the synthetic estrogen, diethylstilbestrol diphosphate (DESdp). Phytohemagglutinin stimulated cultures from three unrelated crossbred steer calves matched for age and weight were divided into dose and time treatments. DESdp was added to the cultures for the entire 72 hour culture period, the last 48 or the last 24 hours at one of the following concentrations: 2.5×10^-5, 2.5×10^-6, 2.5×10^-7, 2.5×10^-8, or 2.5×10^-9 M. Mitotic indices between animals were not significantly different. The duration of treatment had no significant influence on the rate of cell division but the DESdp concentration produced highly significant differences (P<0.01) in the percent of cells undergoing mitosis. Analysis of dose group means failed to demonstrate a linear dose response in mitotic index depression.