Effects of Rabeprazole on Plasma Gastrointestinal Peptides in Healthy Humans

Abstract

Rabeprazole sodium (rabeprazole), a proton pump inhibitor (PPI), is widely used in the treatment of peptic ulcer and gastroesophageal reflux disease. Recently, some antiulcer medicines have been elucidated pharmacologically from the viewpoint of gut-regulated hormone levels. We examined the effects of rabeprazole on plasma levels of gastrointestinal peptides [gastrin, somatostatin, motilin, substance P, and calcitonin generelated peptide (CGRP)]. Rabeprazole at a dose of 20 mg or placebo was orally administered to 5 healthy male volunteers aged 25-30 years. Venous blood samples were taken before and 30, 60, 90, 120, 180, 240, and 360 min after administration. Plasma peptide levels were measured using a sensitive enzyme immunoassay. Compared with the response of the placebo group, rabeprazole caused significant (p < 0.05) increases in gastrin-, somatostatin-, and CGRP-like immunoreactive substance (IS) at 360, 180, and 240 min, respectively. Rabeprazole significantly decreased motilin-IS levels at 180 min compared with the placebo group. However, rabeprazole had no effect on plasma substance P-IS levels. Although rabeprazole has potent antisecretry effects, the agent may have little effect on gastrointestinal peptides.

High performance liquid chromatographic analysis of rabeprazole in human plasma and its pharmacokinetic application

“…1), is a benzimidazole proton-pump inhibitor, which suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase enzyme system at the secretary surface of the gastric parietal cell (Katagiri et al, 2005). Rabeprazole is indicated in the treatment of erosive or ulcerative gastroesophageal reflux disease (GERD), duodenal ulcer, and pathological hypersecretory conditions, including Zollinger Ellison syndrome (Singh et al, 2004;Fujisaki et al, 1991).…”