Methionine-depleting
total parenteral nutrition (
methionine-depleting TPN), which infuses an
amino acid solution devoid of
L-methionine and
L-cysteine as the sole
protein source, showed enhancement of the effect of several anti-
cancer agents. In this study, the combined effect of the
methionine-depleting TPN with the administration of
doxorubicin was examined in
Yoshida sarcoma (YS)-bearing rats with regard to effects on the primary
tumor growth, the extension of
metastasis, and the host animal's life span. In the first experiment, immediately after receiving
methionine-depleting TPN for 8 days, the animals were killed. Pathologic findings evaluated
tumor growth in the implanted site and extension of the
metastasis. In the second experiment, the survival period was determined after animals received
methionine-depleting TPN for 10 days, with subsequent oral feeding until they died naturally. Proliferation of YS was markedly suppressed. In particular, hematogenous
metastasis, which is a characteristic of YS, was suppressed, and a longer survival period (42.7 +/- 15.6 days, mean +/- SD) was attained in rats in the group treated with the
methionine-depleting TPN combined with the administration of
doxorubicin.