Hypergastrinemia in obese noninsulin-dependent diabetes: a possible reflection of high prevalence of vagal dysfunction.

To elucidate the relation of noninsulin-dependent (type II) diabetes mellitus to plasma levels of gastrin, pepsinogen I, and pepsinogen II, gastric acid secretion, and gastric emptying, we studied diabetic and nondiabetic obese Pima Indian subjects. Fasting and postprandial plasma gastrin concentrations were significantly higher (P less than 0.02) in diabetic than in nondiabetic subjects, but gastric acid outputs basally, after an acaloric liquid meal, and in response to betazole were similar in the two groups. Plasma pepsinogen I and pepsinogen II levels were also similar in both groups. A significant negative relation (r = -0.84; P less than 0.01) was found between basal gastrin levels and gastric acid production in nondiabetic Indians, but not in diabetic Pimas. The fractional gastric emptying rate of an acaloric liquid meal was significantly decreased in diabetic Pimas (P less than 0.01); and at least one test showing abnormal vagal function, as estimated by the Valsalva maneuver, heart rate changes between deep expiration and inspiration, and postural hypotension, was found in every diabetic subject. These findings suggest that hypergastrinemia in type II diabetes is not related to hypochlorhydria, but, instead, results from autonomic dysfunction with slow gastric emptying.