The effects of estradiol and progesterone on spontaneous caspase 9 activation at 24 hours assessed by Western blot and densitometry. Total cellular protein was extracted at 24 hours from control neutrophils and cells incubated with estradiol or progesterone (10^-8 g/mL). (A) Pro and active caspase 9 were assessed by Western blot analysis. These blots are representative of 1 of at least 3 separate experiments. (B) Densitometry was performed and the density of each band (percent of total pixels) expressed as the mean ± SD of all blots. *P < .05 versus control at 6 hours.