Effects of restraint and water-immersion stress and insulin on gastric acid secretion in rats

Effects of restraint and water-immersion stress (RWIS) and of insulin injection on gastric acid secretion were investigated in relation to blood glucose levels and to brain glucose uptake in rats. Venous blood glucose levels (VBG) were significantly increased while arterial blood glucose level (ABG) was slightly increased by RWIS. In contrast, ABG and VBG were significantly decreased by administration of insulin; the decrease in ABG was greater than that in VBG. Glucose uptake into the brain, calculated from the ABG-VBG, was significantly decreased both by RWIS loading and by insulin administration. The uptake of [14C] 2-deoxy-D-glucose [( 14C]-2DG) into the brain was also significantly decreased in RWIS-loaded or insulin-treated rats. Gastric acid output was significantly increased both by RWIS loading and by insulin administration. The increased acid output paralleled the decrease of glucose uptake into the brain in RWIS-loaded and insulin-treated rats. Results suggest that RWIS-induced gastric acid secretion is regulated by brain glucose uptake and that this gastric acid secretion is a hypothalamic neuron-mediated event as is insulin-stimulated gastric acid secretion.