The association of increased dihydrofolate reductase with amethopterin resistance in mouse leukemia.

@article{Friedkin1962TheAO,
  title={The association of increased dihydrofolate reductase with amethopterin resistance in mouse leukemia.},
  author={M E Friedkin and E J Crawford and S R Humphreys and Abraham Goldin},
  journal={Cancer research},
  year={1962},
  volume={22},
  pages={600-6}
}
New antifolate-resi slant sublines of mouse leukemia L1210 have been developed. Dihydrofolate reductase activities were determined during early stages of increasing resistance to the folate antagonists. A daily dosage level of 0.75 mg amethopterin/kg used to develop subline FR-1 yielded tumor cells with a tenfold increase of enzyme within three serial transplants. When a new selective influence was imposed by the dichloroamethopterin treatment of mice given implants of amethopterin-resistant… CONTINUE READING