MESSENGER-RNA EXPRESSION OF SOMATOSTATIN RECEPTOR SUBTYPES IN HUMAN AND RAT GASTRIC MUCOSAE

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