GPX1 and adrenal cortex neoplasm: In the current study, we examined the effects of treatment of a mouse model of steroidogenesis, Y1-BS1 adrenocortical tumor cells with pregnenolone, 22(R)-Hydroxycholesterol [22(R)-diol] or hHDL3 on ROS production, phosphorylation status of p38 MAPK and cAMP response element-binding protein (CREB), CREB transcriptional activity and mRNA expression of StAR, CPY11A1/P450scc and antioxidant enzymes, superoxide dismutases [Cu,ZnSOD (SOD1), MnSOD (SOD2)], catalase (CAT) and glutathione peroxidase 1 (GPX1).