FIG. 5.

Effects of wortmannin and U73122 on PKC isoform and MAPK activities. (Top) L6hIR2 cells were incubated with either 50 μM wortmannin or 25 μM U73122 for 30 min and then further exposed to 100 nM insulin for 30 min as indicated. The cells were then solubilized, and lysates (200 μg of protein/sample) were precipitated with isoform-specific PKC antibodies (top) or MAPK antibodies (bottom). PKC and MAPK activities were then assayed in the immunoprecipitates as described in Materials and Methods. Bars represent the means ± standard deviations of duplicate determinations in four (top) and five (bottom) independent experiments.