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.