A Study of the Islands of Langerhans in vivo With Observations on the Circulation

Abstract

Studies of the pancreas with an intact circulation were made in the living animal by Kuhne and Lea, 1 Mathews 2 and Covell. 3

The following report deals with the physiology of the islands of Langerhans in the pancreas of a living mammal with observations on the circulation. The pancreas of the white mouse was the most satisfactory for this purpose. Male mice weighing from 10 to 20 gm. were used. Anesthesia was induced by the subcutaneous injection of 1 mgm. of sodium amytal (Eli Lilly & Co.) per 5 gm. of body weight. After 10 to 20 minutes narcosis was complete. The animal was placed upon its right side in a petri dish that rested upon a warm stage. An incision measuring 1 cm. was made in the left flank, and the anterior pole of the spleen was grasped and drawn through the opening in the abdominal wall. By gentle traction and rotation the tail of the pancreas was brought into view, attached to the hilum of the spleen. After teasing the lobules apart to expose the main central vessels, the pancreas was bathed with physiological saline at 37°C. and covered with a small cover slip. Observations extended one to 2 hours under a binocular microscope using direct illumination.

In suitable preparations the islands could be identified by the naked eye, as minute white dots on a yellow background. They were distributed usually along the course of the main central vessels or branches of the latter. Microscopically they appeared as brilliant yellowish white bodies on the surface of the less refractile yellow pancreas or on a vein. They were round, oval or kidney-shaped, had well defined margins and varied in size from 0.6 to 0.07 mm.