Protection after x-irradiation by 1,4-dithiothreitol of two mammalian cell types in vitro.

1,4-Dithiothreitol (DTT) was found to diminish the amount of chromosomal breakage in leucocyte cultures of the marsupial Potorous tridactylus and in the Don strain of Chinese hamster cells (LHI). The maximum decrease of damage in Potorous lymphocytes was to 54% of that of the irradiated cells without DTT treatment, and to 64% in the case of the Chinese hamster cells. For both cell types, it was shown that the most significant effect of DTT was due to its presence in the first 30 min post irradiation. The protective action of this sulphydryl compound occurred even when DTT was not present during irradiation but was introduced as soon as possible after the X-ray dose was delivered.