Fig. 9. Impact of SV2A and SV2C suppression on hormone secretion. INS-1E cells were transiently co-transfected with a plasmid encoding hGH together with the empty vector (Control), or the SV2A siRNA-3 (siRNA SV2A), or the SV2C siRNA-2 (siRNA SV2C) or with both silencing vectors (siRNAs SV2A/SV2C). Four days later, the cells were incubated with basal 2.5 mM glucose (A-C, open bars) and stimulated for 15 minutes with 30 mM KCl (A, filled bars) or 30 minutes (B, filled bars) or for the indicated period (C, filled bars) with 15 mM glucose. After 10 minutes, an aliquot of the medium was collected (C, left-hand panel) and the incubation was continued for an additional 20-minute period. Secretion between 10 and 30 minutes was calculated by subtracting the amount of hGH released during the first 10 minutes from that for the entire 30-minute incubation (C, right-hand panel). Data represent the mean±s.e. of three or four independent experiments. The conditions indicated by asterisks are significantly different from levels in the control at P<0.05.