Insulin Absorption from the Intestine in Normal and in Depancreatized Dogs. ∗

Abstract

Since the isolation of insulin, the subject of the enteral administration of insulin has excited the interest of investigators. The results reported are somewhat confusing and conflicting.

Bollman and Mann 1 found that “Large amounts of insulin may be instilled directly into the duodenum, jejunum or ileum without any appreciable effect on the sugar of the blood of normal dogs except for the slight effects when concentrated insulin was used.” Bollman and Mann employed doses varying from 100 to 300 units. Murlin, Tomboulian and Pierce 2 report the absorption of insulin from the Thiry-Vella loops of the jejunum in 4 normal dogs, and in 2 of them after pancreatectomy. These observers found that the absorption was aided by the addition of 0.1% HCl, bile and hexylresorcinol.

In a large series of experiments performed during the past 3 years we have invariably obtained the results reported by Bollman and Mann when insulin in dilute acid solution was introduced into an intestinal loops of normal dogs. More recently we have obtained very definite evidence of absorption in normal and especially in diabetic dogs when the insulin was administered with glycol compounds. The most effective of these substances in our experience has been pinacol or tetramethyl-glycol. This compound is solid at room temperature and melts at 42°C. Our preparations have been prepared in the following manner:

The pinacol was melted at 42°C and added to an equal amount of insulin solution, consisting of 1000 units of insulin dissolved in 1 cc of one-tenth normal HCl. This mixture solidifies rapidly, and after standing for a brief period, it was ground into a powder, and this powder pressed into smalll tablets containing 58 units of insulin per tablet. In some preparations the insulin pinacol mixture was heated for one-half hour at a temperature of 110°C and under 10 pounds pressure.