Gene expression in transiently and sustained gastrin treated cells. A: Schematic representation of stimulation protocol. Post confluent AR42J cells were serum starved for 20–24 h before 10 nM gastrin was added. Sustained treated cells (continuous presence of gastrin) were harvested at 9 different time points between 1 and 14 h. Transiently treated cells (gastrin removed after 1 h) were harvested at 8 different time points between 1.5 and 14 h. Untreated control cells were harvested at time point zero and throughout the time course (10 time points). B: Heat map of genes differentially expressed in transiently versus sustained treated cells. Temporal gene expression profiles of genes up- and down-regulated in sustained treated cells compared to untreated controls were hierarchical clustered and matched to temporal gene expression in transiently treated cells compared to untreated controls. The heat map shows average temporal gene expression in two independent experiments. The dendrogram is related to the hierarchical clustering of the first independent experiment with sustained treated cells.