Fig. 5.

Mature OLs are largely resistant to the toxicity of the glutathione-depleting agents BSO (A) or DEM (B). Dose-response curves compare the survival and glutathione content of mature OLs as a function of the concentration of BSO or DEM. Parallel cultures were exposed for 24 hr to BSO or DEM, after which they were assayed for viability with AB, or glutathione was extracted and assayed. A, There was no significant loss of viability at any concentration of BSO tested relative to control. The EC₅₀ for the effect of BSO on the glutathione content of the mature OLs was 0.25 μm.B, The viability at 100 μm DEM was 70 ± 12% of control (NS), and the glutathione content was 0.2 ± 0.03 ng/μg protein. The glutathione content of the cells at 1 mm DEM could not be determined because of complete cell death. Statistical comparisons were by factorial ANOVA.