Gastric function and obesity: gastric emptying, gastric acid secretion, and plasma pepsinogen.

Because rapid gastric emptying and a shortened satiety period might contribute to development of obesity, this study compared gastric emptying of acaloric liquid, gastric acid production, and plasma levels of gastrin and pepsinogen I (PG I) and II (PG II) among obese and nonobese Pima Indians. Rates of fractional gastric emptying and of gastric acid secretion were similar in the two groups, basally and after an acaloric liquid meal. Basal and postprandial plasma gastrin levels did not differ significantly in obese and nonobese Pimas , but peak betazole-stimulated gastric acid output was greater in the obese group, except when normalized by body weight. The plasma PG I and PG II concentrations and PG I/PG II ratio did not differ significantly between the two groups, but the PG I/PG II ratio had a positive correlation with peak acid output. No correlation was found between fractional gastric emptying rate and degree of obesity. We conclude that an increased gastric emptying rate for liquid does not contribute to the pathogenesis of obesity in Pima Indians.