Table 1

Inhibition of F9 cell proliferation by VPA

−VPA+VPA (1 mM)Ratiop
Cell number
 Day 011100%
 Day 1.55.8  ± 0.53.8  ± 0.566%<0.001
 Day 334.4  ± 2.815.6  ± 1.945%<0.001
[3H]Thymidine  incorporation1041  ± 8538  ± 4952%<0.001

Cells were counted in a hemocytometer and values are presented relative to the number at day 0. Values are mean ± S.D. from a total of six determinations in two independent experiments with triplicate cultures each. The ratio of VPA versus nontreated cultures is given. Significance of difference between control and VPA-treated cultures was tested by Student's t test. Thymidine incorporation (cpm) was determined by addition of 1 μCi of [3H]thymidine per culture well for 12 h after 10,000 cells had been cultured for 1.5 days in the absence or presence of VPA on a microtiter culture dish. Values represent the relative recovery of insoluble radioactivity as mean ± S.D. from quadruple determinations. Similar results were obtained in three independent experiments.