A STUDY OF GASTRIC SECRETION CAUSED BY INSULIN

¹ Pavlov Physiological Institute, Battle Creek Sanitarium

1. Both commercial and crystalline preparations of insulin have a definite secretagogue action on gastric glands. The latent period depends upon the mode of administration: ten minutes or less for intravenous and about forty minutes for subcutaneous injection.

2. Duration of secretion depends upon the dosage, lasting from one to six hours (2 to 8 units of insulin).

3. The stimulating action is monophasic and is not preceded by a period of inhibition of gastric secretion.

4. Very small dosages are found to be effective (2 units).

5. Gastric juice secreted in response to insulin has a high acidity, free and total, and high pepsin content. The acidity, determined electrometrically, may attain a pH of 1.0 or even slightly less.

6. It is not improbable that the polypeptide nature of insulin is responsible for its action on the stomach.

7. Gastric secretion caused by this drug, unlike that produced by histamine, is suppressed by the administration of atropin.

8. It is apparent therefore that the secretagogue action of insulin is due to vagus stimulation of the stomach.

9. Intravenous administration of glucose does not suppress gastric secretion produced by insulin.

10. The beginning of gastric secretion precedes the advent of hypoglycemia.

11. The greatest diminution in the amount of blood sugar occurs a considerable time after the onset of secretion.

The secretagogue action of commercial insulin on gastric secretion has been previously demonstrated by other investigators, and some evidence was offered in support of the vagatonic nature of insulin stimulation of the gastric glands (see references).