Antiretroviral protease inhibitors accelerate glutathione export from viable cultured rat neurons.

Antiretroviral protease inhibitors are crucial components of the antiretroviral combination therapy that is successfully used for the treatment of patients with HIV infection. To test whether such protease inhibitors affect the glutathione (GSH) metabolism of neurons, cultured cerebellar granule neurons were exposed to indinavir, nelfinavir, lopinavir or ritonavir. In low micromolar concentrations these antiretroviral protease inhibitors did not acutely compromise the cell viability, but caused a time- and concentration-dependent increase in the accumulation of extracellular GSH which was accompanied by a matching loss in cellular GSH. The stimulating effect by indinavir, lopinavir and ritonavir on GSH export was immediately terminated upon removal of the protease inhibitors, while the nelfinavir-induced stimulated GSH export persisted after washing the cells. The stimulation of neuronal GSH export by protease inhibitors was completely prevented by MK571, an inhibitor of the multidrug resistance protein 1, suggesting that this transporter mediates the accelerated GSH export during exposure of neurons to protease inhibitors. These data suggest that alterations in brain GSH metabolism should be considered as potential side-effects of a treatment with antiretroviral protease inhibitors.