PH does not cause hepatocyte apoptosis in double-transgenic mice expressing ΔN-IκBα. (a) IκBα Western blot. Liver lysates were prepared from mifepristone-treated double-transgenic mice killed 30 minutes or 4 hours after injection of 25 μg/kg TNF (left lanes) or PH (right lanes). (b) Caspase-3 activity measured using substrate DEVD-AMC. Liver protein lysates were prepared from mifepristone-treated single-transgenic and double-transgenic mice killed at the indicated times after PH. The last column (4 + TNF) represents mice injected with 25 μg/kg TNF 30 minutes prior to PH and killed 4 hours after surgery. Data represent average (± SEM) caspase activity measured in each group. Three mice were used per group. *P < 0.05 for double-transgenic compared with single-transgenic mice. (c) Bcl-xL Northern blot (top panel) and loading control cyclophilin (bottom panel).