| Abstract: | Among tumors in general, Ehrlich ascites tumor cells are particularly resistant to lipid peroxidation. In this study lipid peroxidation was measured in terms of the formation of malondialdehyde-equivalent material in Ehrlich tumor cells during incubation in vitro. It was shown that the high antioxidant potential of these cells could be overcome by a strong radical-promoting agent like ferrous ion. Various amino acids were tested for their capability to augment the effect of Fe(II). Histidine and its 3-methyl-derivative turned out to be the most effective pro-oxidants, whose action could be ascribed to the presence of the imidazole group. From studies with homogenized and denatured cells it was concluded that lipid peroxidation stimulated by Fe(II)-histidinate is an autoxidation process and that no carrier effect of iron by histidine is predominating. The stimulatory action of Fe(II)-histidinate could be completely suppressed by vitamin C, which was shown to be a potent anti-oxidant under the conditions used. The combined application of Fe(II)-histidinate and vitamin C may offer a means to study lipid peroxidation of Ehrlich tumor cells in a controlled manner. |
