Studies have been made on the effect of multiple injections of ethionine alone and with arginine, glycine, or lysine on the carcass weight, growth of Sarcoma R-1, and free and combined (nonprotein) amino acids in the livers of male Wistar rats. Carcass weights were decreased, and the tumor growth was inhibited to about the same degree by ethionine as by ethionine-amino acid combinations.
With the exception of methionine, serine, and arginine, the free and bound (nonprotein) amino acids in the livers of tumorous rats generally increased percentage-wise to about the same extent following injections of ethionine or of ethionine plus an amino acid. Higher concentrations of nonprotein amino acids were observed following multiple injections of ethionine or ethionine and lysine than were obtained with a single injection of these substances.
Paper No. 107. For the preceding related paper (No. 103), see Levy et al. (9). This work was supported by grants from Swift & Company, the American Cancer Society, the U.S. Public Health Service, and the Cancer Research Funds of the University of California. The authors are indebted to Mrs. Grace Davis and Miss Sally Lovett for technical assistance.