Highly histamine-responsive clones from the human gastric adenocarcinoma cell line HGT-1

The human gastric epithelial cell line HGT-1 possesses adenylate cyclase-coupled histamine H2 receptors. To test the cellular homogeneity or heterogeneity with respect to these receptors, we have isolated 7 clones from the HGT-1 line and studied their basal and histamine-stimulated adenylate cyclase activities. Basal adenylate cyclase activities of the clones did not differ significantly, nor did 10 mM NaF- nor 0.1 mM Gpp(NH)p-stimulated activities. However, histamine stimulation of adenylate cyclase varied among clones from 1.9 fold to 5.4 fold basal activity. The EC50 values, determined in 3 clones, were not significantly different. These findings support the heterogeneity of histamine responsiveness of the human gastric cell line HGT-1. In addition, they suggest that highly histamine-responsive clones may be useful models to study the gastric histamine H2-receptor and its specific antagonists in the human.