Effect of ethionine alone or with amino acids on tumor growth, carcass weight, and nonprotein amino acids in rat liver.

Studies have been made previously on the ef fect of ethionine on the free amino acids in the livers of tumorous and nontumorous rats of the Long-Evans (6, 8), Sprague-Dawley (13), and Wistar (9) strains. Attempts at dual blocking, with pairs of antimetabolites, have also been re ported (12). The observation that certain amino acids may function as antimetabolites in inhibiting tumor growth (3, 7) led to the present study of at tempted dual blocking by multiple injections of ethionine alone and in combination with various amino acids.