Studies on the Effectiveness of Insulin Implants

Abstract

Ever since an active preparation of insulin was secured, methods have been sought for administering the hormone by some means other than injection. Major¹ reviewed the results which had been reported up to 1936. Since then numerous reports have been published, of which the following summarizes the more pertinent findings.

Parkes and Young² in experiments on rabbits found that the hypoglycemic action of amorphous insulin pellets was only slightly more prolonged than that of a similar amount of insulin in solution administered subcutaneously. Crystalline insulin pellets had a similar duration of action despite the fact that the tissue capsule around the pellet contained appreciable amounts of insulin.

Using depancreatized dogs Mark et al³ found that pellets of crystalline zinc insulin with protamine were effective for as long as 100 hours. The pellets on examination four hours after implantation were swollen, and there was edema at the site of implantation.

Cutting et al⁴ reported briefly on the effective use of pellets of cholesterol and insulin in depancreatized dogs. They observed a slow release of insulin during periods as long as 13 days. The irregularities of absorption were too great to justify the trial of such pellets in the clinical treatment of diabetes.

EXPERIMENTAL

Methods. Adult dogs maintained on a constant diet were used. They were fed at 3 p. m. daily. Blood was drawn from the saphenous vein when the dog was in the postabsorptive state. All excitement was carefully avoided. Blood sugar was determined by the Somogyi modification of the. . .