Decreased sensitivity to colchicine-mediated inhibition of metabolite uptake in isolated hepatoma cells

The effects of colchicine on the incorporation of [³H]-leucine and [³H]thymidine were studied in inbred BUF rats bearing Morris hepatomas and in isolated hepatoma cells and hepatocytes. The results confirmed previous work by other investigators that uptake of amino acids in hepatomas can be inhibited by colchicine (250 μg/100 body wt) under conditions in wich uptake is not impeded in host liver. Uptake and incorporation of [³H]thymidine in hepatomas were also more sensitive to inhibition by colchicine. Evidence was obtained that these inhibitory effects on incorporation were diminished in isolated cells and were similar for isolated hepatoma cells and hepatocytes. The data did not exclude alternative mechanisms, but they were compatible with a previous suggestion that an effect of colchicine on circulation in hepatomas may be a factor in the inhibitory action on metabolite uptake.