Messenger RNA expression of somatostatin receptor subtypes in human and rat gastric mucosae.

In several tissues including gastric mucosa, somatostatin displays various biological effects. Five seven-transmembrane-domain somatostatin receptor subtypes (SSTR1-5) have been recently cloned and only SSTR1 has been shown to be present in the human stomach. We used the polymerase chain reaction on reverse transcripts (RT-PCR) to characterize further the SSTR's mRNAs in human and rat gastric mucosae and in the human gastric tumoral cell-line HGTL. The SSTR1-5's mRNAs were found in both human fundic and antral mucosae as well as in the HGT1 cell and rat antrum. The four SSTR2-5's mRNA's but not SSTR1's were detected in the rat fundic mucosa. Furthermore, the use of rat isolated and purified fundic mucosal cells allowed us to localize SSTR2-5 in the parietal cell-enriched fraction, whereas SSTR2 and SSTR5 were the only subtypes found in the endocrine cell-enriched fraction. These results are the first to demonstrate the presence of five SSTR's mRNA subtypes in the stomach.