Prolonged treatment of monocytes with GCs leads to increased resistance to STS-induced apoptosis, which is accompanied by diminished caspase activity. Monocytes were cultured in the presence of different concentration of DEX for 2 days. Subsequently cells were stimulated to undergo apoptosis by STS (■) or left untreated (□). After 6 hours, amounts of annexin V–positive cells were measured (A). Monocytes were incubated for 2 days with 100nM DEX (GC) or medium (Co). Cells were stimulated with medium as a control (□) or with STS (■). After indicated points of time, STS-induced apoptosis was evaluated by annexin V staining (B) and Nicoletti assay (C). Simultaneously, cell lysates were prepared and incubated with the caspase-9 substrate Ac-LEHD-AMC (D), caspase-3 substrate Ac-DEVD-AMC (E), and caspase-8 substrate Ac-IEPD-AMC (F). The fluorometric determination of AMC release was expressed as a fluorescence increased (ΔF) per microgram of cell protein. Data represent mean ± SEM (n = 3).