Effect of nitidine chloride on the life cycle of ehrlich ascites carcinoma cells in mice

The effect of nitidine-Cl on the life cycle of Ehrlich ascites carcinoma (EAC) cells in CFW mice was studied by radioautography. The EAC cells were labeled on the 4th day after ip inoculation of 1*10(7) cells. The Tc of the cells was found to be 38.8 h. The T(G1), T(S), T(G2) and T(M) were 8.0, 25.8, 3.8 and 1.2 h, respectively. The growth fraction was 0.86. When nitidine-Cl 20 mg/kg was given ip, the [3H]TdR pulse labeling index of EAC cells was unaffected within 26 h, but the mitotic index was reduced and the size of the cells increased, which suggested a G2 block. The cells in S phase might be killed by nitidine-Cl 40 mg/kg. When the cells were labeled with [3H]TdR or [3H]UdR, the average labeling grain counts per cell revealed that the synthesis of DNA and RNA could be inhibited by nitidine-Cl 20 mg/kg.