Studies in dogs on the biphasic nature of the gastric secretory response to hypoglycaemia and other stimuli with special reference to the role of the adrenals.

The gastric secretory response of dogs with fundal pouches to insulin hypoglycaemia is biphasic in character, the two secretory peaks being separated by some hours. The first response depends on the intact innervation of the pouch and is attributed to direct vagal action on the parietal cell. Experiments have been made to test the hypothesis that the second peak is due to activation of a pituitary adrenal mechanism.The second phasic response does not depend on the intact innervation of the pouch and does not coincide with the period of hypoglycaemia. No relationship has been established with the second phase and plasma cortisol levels nor is this peak abolished by bilateral adrenalectomy. The second acid secretory response, however, is only evident when acid secretion of the main stomach makes prolonged contact with the antral mucosa; it is abolished by antrectomy. The hypothesis is put forward that the pattern of response following insulin hypoglycaemia after the initial vagal response is attributable to an interaction of acid-inhibiting and acid-stimulating mechanisms of gastric acid secretion mediated through the gastric antrum.