Effects of uracil nucleotides in cell proliferation. Lipopolysaccharide (LPS) cultures were incubated with nucleotides for 48 h and in the last 24 h methyl-[3H]-thymidine was added to the medium at a concentration of 1 μCi/ml. Effects in cell proliferation were estimated by methyl-[3H]-thymidine incorporation and expressed in percentage of control. Values are means ± SEM from five to ten experiments. *P <0.05, significant differences from control.