Factors contributing to the resistance of the thyrocyte to hydrogen peroxide.

We studied the mechanism that may explain the relative resistance of thyrocytes to HO compared to other cell types. Ability to degrade HO, glutathione peroxidase (GPx) activity, heme oxygenase-1 (HO-1) expression, cell survival and capacity to repair DNA damage after HO exposure or irradiation were measured in human thyrocytes in primary culture and compared to the values obtained in human T-cells and different cell lines. Compared to other cell types, thyrocytes presented a low mortality rate after HO exposure, rapidly degraded extracellular HO and presented a high basal seleno-dependent GPx activity.