[Resistance of a line of Djungarian hamster cells to 6-mercaptopurine].

A cell line resistant to 6-mercaptopurine (6-MP) is isolated from Djungarian hamster embryonic fibroblasts transformed with SV-40, 6-MP resistance is due to the absence or complete inhibition of GGPRT activity. Initial and resistant cell cultures are similar in the growth rate and in the inoculation efficiency. Caryological analysis (differential chromosome staining--S-bands) revealed considerable caryotype rearrangements in both resistant and sensitive lines as compared with Djungarian hamster normal chromosome set, and also the appearance of specific chromosome markers.