Diabetes Mellitus : Part 2

Diabetes: Prevention, Control, and Cure
By Seymour L. Alterman, M.D., Donald A. Kullman, M.D.

(Page 2 of 2)

The brain, our body's most important organ, relies primarily on glucose for fuel. It has evolved its own glucose regulatory mechanisms to ensure an adequate, continuous fuel supply. A special glucose-monitoring sensor within the brain responds to rapid falls in the blood sugar level by stimulating the adrenal glands to secrete epinephrine, another insulin antagonist hormone. Epinephrine is responsible for causing many of the symptoms associated with mild episodes of hypoglycemia (low blood sugar).

There are two main types of diabetes mellitus. Type 1 diabetes arises from the destruction of the insulin-producing beta cells of the pancreas, which causes an absolute deficiency of insulin. Without daily injections of insulin to replace what their bodies cannot produce, type 1s are unable to survive. In type 2 diabetes, the pancreas produces insulin, but the body's cells become resistant to its glucose lowering action-an inability to use it efficiently. Before future Type 2s develop diabetes, their bodies require extra insulin to keep their blood sugar within the normal range.This compensatory mechanism of increased insulin output by the pancreas may suceed in controlling the blood sugar for years. However, over time, as insulin resistance gradually increases and the tired, overworked pancreas's output of insulin decreases, the blood sugar rises-initially to levels beyond normal but below those needed to make a diagnosis of diabetes, the so-called impaired glucose tolerance phase. Eventually, the blood sugar rises to diabetic levels and the patient becomes symptomatic.

In type 2 diabetes, the body manufactures the insulin keys, but many of the cell door locks (insulin receptors) are blocked or defective, which prevents the insulin keys from doing their job.

Historical Perspective

Diabetes is an ancient disorder, recognized by its symptoms as early as 1500 B.C. in an Egyptian medical text called the Ebers Papyrus. In the second century A.D., Aretaeus, a Greek physician, gave the disease its present name from a Greek word meaning "to run through a siphon" (originally referring to the large volume of urine excreted in uncontrolled diabetes). The Latin word for honey, mellitus, appeared much later, and was employed to describe the honeylike odor and sweet taste of the urine. In 1775, Matthew Dobson, an Englishman, proved that the sweet taste of the urine of diabetics was actually due to sugar. In the 1860s, a medical student, Paul Langerhans, identified the patches of unique cells, scattered as small islands throughout the pancreas, which now bear his name. In 1889, two German physiologists, Drs. Von Mering and Minkowski, were the first to note that removal of the pancreas caused the syndrome known as diabetes mellitus. It was later demonstrated that the Islets of Langerhans actually manufactured, stored, and released the hormone insulin into the bloodstream.

For centuries, the symptoms of diabetes-marked thirst, frequency of urination, and weight loss-were well known. As the disease progressed, patients would try the various nostrums of the day: special diets, fasting, opium, barley water, and even blood-letting. Of course, these therapeutic efforts were to no avail because the real culprit was an absolute or a relative absence of the hormone insulin. As recently as the first two decades of the 1900s, there was no unanimity of medical opinion about the type of diet and medications that should be prescribed for diabetics. Most physicians speculated that a low carbohydrate diet would be beneficial. However, some believed that the sugar lost in the urine should be replaced and, accordingly, recommended a high carbohydrate diet. The guesswork treatment of diabetes came to an abrupt end in 1921 when a young surgeon, Frederick Banting, with the assistance of Charles H. Best, a medical student working in the physiology department at the University of Toronto, made an extract of the tiny pancreatic islet cells. When injected into laboratory animals, the extract caused a dramatic fall in blood sugar levels. Soon, human patients with diabetes were given this "new insulin treatment," and the modern era of what had been a long and dismal history of diabetes treatment was to begin. Dr. Banting received the Nobel Prize for this important discovery.

Purification and standardization of insulin was undertaken, and prolongation of its action was finally achieved by adding proteins and zinc to the insulin extracted from animals, primarily cows and pigs. Today we use "human" insulin made semisynthetically from pork insulin, or biologically engineered, utilizing complicated recombinant-DNA technology. This has been of great value in reducing the allergic reactions that were sometimes seen with animal insulins.

In later chapters, we shall take an in-depth look at the different types of insulin and their use, as well as oral anti-diabetic medications.

Copyright © 2006 by Seymour L. Alterman, M.D.

About the Author

Seymour L. Alterman, M.D., F.A.C.P., is Clinical Professor of Medicine and Endocrinology at the University of Miami School of Medicine. He is certified by the American Board of Internal Medicine in Endocrinology and Metabolism.

Donald A. Kullman, M.D., has been practicing family medicine for more than forty years and is the editor of several medical books.