Purpose of review: Update on the role of gastrointestinal peptides in regulating gastric acid secretion.
Recent findings: A novel transgenic mouse that expresses the entire human gastrin gene locus in G-cells of gastrin-null mice will facilitate investigation of gastrin gene regulatory elements. Isolation of a highly homogeneous population of G-cells permits the elucidation of stimulatory and inhibitory ligands without the confounding presence of other neuroendocrine cells. The use of somatostatin receptor knockout mice demonstrated the plasticity of gastric acid regulatory mechanisms and compensation by upregulation of the galanin pathway which inhibits secretion by enterochromaffin-like cells. The importance of adenosine in regulating somatostatin release was shown using adenosine receptor knockout mice.
Summary: The importance of gastrointestinal peptides for regulating gastric acid is evident. Ongoing investigations will characterize the mechanisms underlying actions of these agents on gastric acid secretion, particularly with regard to their combinatorial effects and interplay with other acid-regulating pathways.