Urinary polyamine excretion by tumor-bearing and tumor-free mice exposed to cyclophosphamide, 5-fluorouracil and 6-mercaptopurine.

The effects of cytostatic treatment on urinary polyamine excretion have been investigated in tumor-bearing (either Ehrlich carcinoma of S 180 sarcoma) and in tumor-free mice. The animals were exposed to single or multiple treatment with various doses of cyclophosphamide, 5-fluorouracil, or 6-mercaptopurine. Treatment invariably enhanced polyamine excretion dependent on dose and effectiveness of the cytostatic drug. The most pronounced increases were observed in the excretion of spermine and putrescine, with peak excretion usually occurring after 1-2 and 3-4 days, respectively. The urinary excretion of spermidine was relatively modest in untreated mice, but the increases observed following drug treatment were high in proportion. Significant differences in urinary polyamine excretion were observed between tumor-free and tumor-bearing animals following treatment with all cytostatic agents. Peak values were invariably higher in tumor-bearing mice even in those with small, barely detectable tumors. After discontinuation of treatment polyamine excretion returned to normal values and stabilized in groups in which regression predominated, whereas in those groups of animals which showed little or no tumor regression urinary polyamine levels gradually increased again during a 2-week observation period.