Figure 4: IGF1 has biphasic effects on XIAP protein expression. (a) Western blot assays of VH-64 cell lysates with antibodies to XIAP, Bax, and Mcl-1. Cells were treated for the indicated times with IGF1 (100 ng/mL). Representative nonstripped blots separately probed with the different antibodies are shown. (b) EIA analysis of XIAP in cells incubated for the indicated times with IGF1 (100 ng/mL). Asterisks: * , ** ; error bars: mean ± SD of triplicate determinations from 4 independent experiments.