Effect of combined chemotherapy tested in partially hepatectomized rats bearing Zajdela hepatoma.

: Ascitic Zajdela hepatoma growing in partially hepatectomized rats was used for testing cytostatics in single and two-drugs combination chemotherapy. At the optimal dosage the highest selective activity against tumor cells (hepatoma) with low inhibition of normal cells (regenerating liver cells) was seen in the combination cis-platinum + methotrexate. Synergistic effect of this combination was found when suboptimal dose of MTX was combined with low doses of cis-Pt. Dose-dependent DNA synthesis inhibition following i.p. administration of cis-Pt was documented by 3H-thymidine incorporation. Although the content of platinum expressed per DNA amount was four times higher in regenerating hepatocytes when compared with hepatoma cells, the growth inhibiting effect of cis-Pt was selectively expressed against the hepatoma cells.