GASTRIN RECEPTOR GENES ARE EXPRESSED IN GASTRIC PARIETAL AND ENTEROCHROMAFFIN-LIKE CELLS OF MASTOMYS-NATALENSIS

Although gastric enterochromaffin-like (ECL) carcinoid tumors are know n to develop in patients with long-standing hypergastrinemia, the expr ession of the gastrin receptor gene in ECL cells has not yet been demo nstrated. Therefore this study was designed to examine gastrin recepto r gene expression in ECL cells. Mastomys gastric mucosal cells isolate d by enzyme dispersion were separated into 10 fractions (F1-IO) by cen trifugal elutriation. Each fraction was examined histologically to det ermine whether they contained ECL and/or parietal cells and Northern b lot analysis was used to confirm the presence of histidine decarboxyla se and H+, K+-ATPase gene expression. ECL cells were found only in fra ctions 1 and 2, whereas parietal cells were detected in fractions 6-10 . Gastrin receptor gene expression was demonstrated in both parietal c ell-rich and ECL cell-rich fractions. In addition, the gastrin recepto r cDNA sequences obtained from the two of the fractions (F1 and 8) wer e identical. These results suggest that gastrin receptor genes are exp ressed in ECL cells as well as in parietal cells and that these recept ors are identical.