An important component of the neuroprotec¬tive mechanisms of oestradiol is the regulation of B cell lymphoma 2 (BCL 2) family members that are involved in the control of apoptosis (FIG. 3). In the brain, oestradiol upregulates the expression of anti apoptotic BCL 2 family members, such as BCL 2 (REFS 78–82), BCL XL83–85 and BCL W86, and downregulates the expression of pro apoptotic BCL 2 family members, such as BCL-associated death promoter (BAD)87 and BCL-2 interacting mediator of cell death (BIM)86. Both ERα and ERβ mediate the oestradiol-induced increase in the expression of BCL 2 in hippocampal neurons88.