The effects of inflammatory cytokines induced by Helicobacter pylori infection on acid secretion have not been well defined. The purpose of this study was to investigate the direct effects of these cytokines on parietal cells isolated from guinea pigs. We examined the effects of human recombinant IL-1beta (0.05-100 ng/ml), IL-8 (2-256 ng/ml), and TNF-alpha (0.625-80 ng/ml) on acid secretion stimulated by three secretagogues (10(-4) M histamine, 10(-4) M carbachol, and 10(-5) M tetragastrin) and on basal acid secretion from isolated parietal cells, which was measured by the aminopyrine accumulation method. None of three cytokines showed any significant effects on stimulated or basal acid secretion from isolated guinea pig parietal cells. We concluded that inflammatory cytokines induced by Helicobacter pylori infection may affect acid secretion through mechanisms other than direct actions on parietal cells.