Effect of Adrenocorticotrophic Hormone Upon the Gastric Secretion of Hydrochloric Acid, Pepsin and Electrolytes in the Dog

Abstract

The effect of ACTH on gastric secretion of pepsin, acid, Cl, Na and K in the dog was studied by collecting gastric juice through gastrostomy tubes from the intact stomach before and after vagotomy, and from the Heidenhain pouch and gastric remnant simultaneously. Response to ACTH was also studied after antrectomy, unilateral adrenalectomy, and bilateral adrenalectomy. Changes in osmolality of gastric juice and serum after ACTH administration, and the effect of the carbonic anhydrase inhibitor (Diamox) upon the ACTH response were likewise determined. A single injection of ACTH to dogs produced a significant increase in gastric acidity, pepsin and Cl after a latent period of 3-4 hours, attaining a maximum in 4-6 hours. This was accompanied by a fall in gastric juice Na and K. An increase in volume of secretion was shown in Heidenhain pouch dogs. The gastric secretory response to ACTH was not altered by vagal denervation, or antrectomy, but was abolished by bilateral adrenalectomy. Diamox failed to inhibit gastric acid hypersecretion following ACTH stimulation. Increase in osmolality of gastric juice was shown 4 hours after administration of ACTH without any change in the serum osmolality. The stress of unilateral adrenalectomy produced marked rise in gastric acid and pepsin secretion. All experiments were performed upon unrestrained dogs in their own cages, emphasizing the importance of this approach to the study of gastric secretion. These studies demonstrate a hormonal mechanism for gastric secretion mediated through the adrenal gland and independent of the vagus nerve or gastric antrum.