EFFECT OF METHOTREXATE ON THE INTRACELLULAR PHOSPHORIBOSYL PYROPHOSPHATE LEVEL AND GLUCOSE-TRANSPORT OF EHRLICH ASCITES TUMOR-CELLS IN-VITRO

Methotrexate (MTX) suppressed the growth of Ehrlich ascites tumor (EAT ) cells in vitro. The intracellular level of phosphoribosyl 5-pyrophos phate (PRPP) of EAT cells increased in a dose-dependent manner in resp onse to MTX treatment. At the same time, the rate of glucose transport was lowered. Hypoxanthine reversed both these effects of MTX and part ially rescued EAT cell growth. Under all conditions tested, changes in rate of glucose transport were shown to be the result of alterations in the number of glucose transporter (V-max) rather than ligand affini ty (K-m). The dual action of MTX as a chemotherapeutic agent is discus sed in this light.