Effects of estrogens on caspase-3 protein levels during glutamate (5 mM) induced cell death in primary cortical cells. Cortical cells isolated from 19 day old fetal rat brains were cultured for 7 days and treated with 5 mM glutamate alone or in the presence of 17β-E2 and Δ8, 17β-E2 for 6 h. Cells were then harvested and total protein was extracted. Caspase-3 protein levels were determined by Western blot analysis as described under Figure 6. The bars depict densitometric analyses of Western blots from at least three experiments (± SEM). a = P < 0.05 compared with untreated control cells, b = P < 0.05 compared with glutamate alone.