Fig. 2.

PACAP and PMA stimulation of VIP biosynthesis are differentially sensitive to blockade by inhibitors of protein kinase C. Chromaffin cells were pretreated for 30 min with vehicle (0.1% DMSO), the protein kinase C inhibitors Gö6983 (1 μm), or chelerythrine (Chel; 5 μm), and additionally for 24 hr with vehicle, 100 nm PMA, or 100 nm PACAP-27 with or without the PKC inhibitors. Cells and mediums were harvested for VIP radioimmunoassay as described in Materials and Methods and expressed as the fold increase in VIP immunoreactivity per well compared with the corresponding control. Values represent the mean ± SEM of three individual wells from a single cell dispersion. *Different from corresponding control atp < 0.001; Scheffe's post hocanalysis. Control values were as follows: vehicle, 41 ± 2.8 pg per well; Gö6983, 24.2 ± pg per well; chelerythrine, 27.2 ± 3.0 pg per well.