Efficacy of intra-arterial norcantharidin in suppressing tumour 14C-labelled glucose oxidative metabolism in rat Morris hepatoma.

Norcantharidin is the demethylated form of Cantharidin, which is the active ingredient of the blister beetle, Mylabris, a long used Chinese traditional medicine. Though not well publicized outside China, Norcantharidin is known to possess significant anti-hepatoma activity, and is relatively free from side effects. In the present study, glucose oxidation in tumour and liver tissue slices harvested from hepatoma-bearing animals was quantified by measuring the radioactivity of 14C-labelled CO2 released from 14C-glucose in oxygen-enriched incubation medium. Results were expressed as a tumour/liver ratio. For comparison, treatments with Norcantharidin, Adriamycin and with hepatic artery ligation were studied. The mean tumour/liver ratio was 4.2 +/- 2.2 in untreated controls, but dropped significantly to 2.3 +/- 0.5 (p < 0.05) with intra-arterial Norcantharidin (0.5 mg/kg) and to 2.3 +/- 0.7 (p < 0.05) with intra-arterial Adriamycin (2.4 mg/kg), and to 2.2 +/- 0.7 (p < 0.05) with hepatic artery ligation. However, with intravenous Adriamycin at 2.4 mg/kg, the mean tumour/liver ratio was reduced to only 3.5 +/- 2.0 and was not significantly different from untreated controls. It is concluded that intra-arterial Norcantharidin is as effective as intraarterial Adriamycin and hepatic artery ligation in suppressing tumour glucose oxidative metabolism. These result simply that Norcantharidin may have a role to play in the chemotherapy of primary liver cancer.