Somatostatin release from perifused rat and human gastric mucosa.

In the present study the release of somatostatin-like immunoreactivity (SLI) was evaluated in vitro from isolated rat antral and fundic mucosa and from biopsy specimens of human antral mucosa. Perifusion of antral mucosa with Earle's balanced salt solution showed a pH-dependent release of SLI. SLI release did not change in response to a reduction from pH 7 during the baseline period to pH 3, whereas a significant increase occurred when the pH was changed to 2.5 or 2, respectively. Fundic SLI release remained at baseline levels during the decrease of the pH value of the buffer solutions. Atropine at doses of 10(-6) to 10(-4) M did not alter acid-induced SLI release from the isolated antral mucosa, suggesting different mechanisms in vitro compared to the acid-induced SLI release in vivo. SLI release from human mucosa was 450 +/- 217 pg/min X mg wet weight in response to perifusion with the buffer pH 2 in 7 control subjects. No significant difference was observed in patients with duodenal ulcer or acute gastritis, whereas gastric ulcer patients had significantly lower values (66 +/- 44) compared to controls and duodenal ulcer patients. These data do not support the hypothesis that impaired somatostatin production and release might be a pathogenetic factor for gastric acid hypersecretion and development of duodenal ulcer.