["Helicobacter pylori is known to affect the host's nutritional status. This study was performed to elucidate the relationship between H. pylori status and the dynamics of the ghrelin system, in the context of ghrelin O-acyltransferase (GOAT) expression.", 'We conducted a clinical study of 30 subjects focusing on the following points: 1) the effects of H. pylori infection on the concentrations of circulating ghrelin isoforms and on ghrelin and GOAT mRNA expression in the gastric mucosa, and 2) the effects of H. pylori eradication on the same parameters.', 'The plasma acyl-ghrelin and desacyl-ghrelin concentrations of 16 H. pylori positive participants were significantly lower than those of 14 H. pylori negative controls. The acyl-ghrelin/desacyl-ghrelin ratio was not significantly different between the H. pylori positive and H. pylori negative participants. The levels of ghrelin and GOAT mRNA in the gastric mucosa were significantly lower in the H. pylori positive participants than in the H. pylori negative controls. In 11 subjects in whom H. pylori eradication was successful, their plasma acyl-ghrelin levels tended to increase after H. pylori eradication, but the difference was not significant; however, their plasma desacyl-ghrelin levels were significantly reduced. Although gastric ghrelin mRNA expression increased significantly after H. pylori eradication, gastric GOAT mRNA expression tended to increase but was not significantly altered.'] Are plasma ghrelin isoforms and gastric ghrelin O-acyltransferase expression influenced by Helicobacter pylori status?