The inhibition of thymidine metabolism in tumor cells treated with D-glucosamine.

The amino sugar, D-glucosamine, inhibits the preformed route of thymidine metabolism in rat C6 glioma cells. This inhibition results from a concatenation of several distinct effects, including the inhibition of thymidine uptake, the reduction of thymidine phosphorylation, and an increased leakage of thymidine to the extracellular space. Each of these effects, while ostensibly small in magnitude, is significant and contributes to the observed inhibition of acid-precipitable thymidine incorporation by D-glucosamine. These effects of D-glucosamine, together with its known ability to reduce uridine nucleotide pools, may contribute to its toxicity toward certain experimental animal tumors.