Effects of Omeprazole on Gastric and Duodenal Bicarbonate Secretion

Abstract

The stomach and duodenum in a variety of species, including man, secrete HCO₃⁻ into the lumen by processes that are dependent on cell metabolism (1). This secretion must be distinguished from the passive diffusion and ultra-filtration of HCO₃⁻ across already damaged epithelia, and is probably an important factor in mucosal protection against acid. It maintains the pH in the viscoelastic mucous gel adherent to these epithelia at neutrality, in spite of a lumen pH as low as 1.5–2.5, thus providing a first line of defence against acid (1, 2). The effects of omeprazole on gastric and duodenal HCO₃⁻ secretion have been studied and are reported here.