5-Fluorouracil (5-FU) metabolism on
tumors was studied by in-vivo 19F-MRS (magnetic resonance spectroscopy). In this study, two kinds of
tumors were used, i.e.,
Yoshida sarcoma implanted subcutaneously to the abdomen of rats and
drug-induced
tumors in the rats livers. Sequential 19F spectra were obtained just after 150 mg/kg
5-FU injected intravenously. In
Yoshida sarcoma, the accumulation of
5-FU was observed and disappearance of
5-FU was slower compared to the normal tissue. However, synthesis of fluoronucleotides (Fnct) could not be detected. In
drug-induced liver
tumors, the peak of fluoro-
beta-alanine (
FBAL) was observed. Disappearance of
5-FU and catabolism to
FBAL in the liver
tumors group were slower compared to the normal liver. Synthesis of Fnct did not increase in the liver
tumor group. The results in the liver
tumor group are considered to be the confined result of the hepatocytes and
tumors cells. It was considered that the delayed catabolism to
FBAL in the liver
tumor group showed metabolic dysfunction of the liver. Also the synthesis of Fnct in
tumors could not be detected by in-vivo 19F-MRS. 19F-MRS method could not detect Fnct in
tumors in-vivo. However, the accumulation of
5-FU could be assessed by this method. It is expected that the evaluation of
5-FU pooling in
tumors could be used for the index of chemotherapeutic effect.