On March 17, 1949, the Frank E. Bunts Educational Institute presented a continuation course on Diabetes. There follow abstracts of the proceedings of this course.
THE PHYSIOLOGY OF INSULIN
E. Perry McCullagh, M.D.
Insulin comes from the islets of Langerhans, which are groups of about 30 cells weighing 1/120 of the weight of the pancreas. These cells are of several types; the alpha and beta cells are granulated, suggesting secreting power. The fact that insulin arises in the islet cells is supported by the fact that it is present when enzyme tissue is degenerated; moreover, it is present in adenomata or carcinomata of islet tissue. Its production is influenced either by pituitary extracts or alloxan, the effects of which are shown in microscopic changes of the islet cells, especially the beta cells.
Insulin, first produced in extracts by Banting and his co-workers in 1922, was crystallized by Abel in 1926. It is an interesting fact that it contains zinc. The hormone is a polypeptide of approximately the molecular weight of egg albumen. One of the most potent factors regulating insulin production is the amount of glucose reaching the pancreas in arterial blood.
Some of the important functions of insulin may be listed as follows:
It regulates blood glucose levels.
It effects the storage of glycogen in liver and muscles.
It influences utilization of sugar by the tissues.
It increases fixation of amino acids in tissues for production of protein.
It has indirect action on hepatic. . .