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Discovery of Insulin

Discovery of Insulin -

The Nobel Prize in Physiology or Medicine 1923 was awarded jointly to Frederick Grant Banting and John James Rickard Macleod 

Before the discovery of insulin, diabetes was a feared disease that most certainly led to death. Doctors knew that sugar worsened the condition of diabetic patients and the most effective treatment was to put the patients on very strict diets where sugar intake was kept to a minimum. At best, this treatment could buy patients a few extra years, but it never saved them. In some cases, the harsh diets even caused patients to die of starvation.

During the nineteenth century, observations of patients who died of diabetes often showed that the pancreas was damaged. In 1869, a German medical student, Paul Langerhans, found that within the pancreatic tissue that produces digestive juices there were clusters of cells whose function was unknown. Some of these cells were eventually shown to be the insulin-producing beta cells. Later, in honor of the person who discovered them, the cell clusters were named the islets of Langerhans.In 1889 in Germany, physiologist Oskar Minkowski and physician Joseph von Mering, showed that if the pancreas was removed from a dog, the animal got diabetes. But if the duct through which the pancreatic juices flow to the intestine was ligated - surgically tied off so the juices couldn't reach the intestine - the dog developed minor digestive problems but no diabetes. So it seemed that the pancreas must have at least two functions:·        

• To produce digestive juices·         
• To produce a substance that regulates the sugar glucose

This hypothetical internal secretion was the key. If a substance could actually be isolated, the mystery of diabetes would be solved.

Birth of an idea
Dr. Banting was working as a part-time instructor at the university when, during a sleepless night on October 31, 1920, he was reading a medical journal during which an idea suddenly clicked in his mind.  His idea was aimed at isolating the internal secretion of the pancreas, a jelly-like gland behind the stomach. He recalled from his lectures at medical school that this secretion supposedly regulated sugar in the bloodstream. If he could isolate this secretion, it might hold the key in the treatment of diabetes.  

Work begins
Banting began working in the laboratory of J.J.R. Macleod at the University of Toronto together with his medical student Charles Best conducting experiments on dogs. They persevered, testing their extract on dogs. It was long and arduous work and few believed they would succeed. But eventually, their diligence paid off. The principal symptom of diabetes is a high level of sugar in the blood. To Dr. Banting's delight, injections of the extract, which he would later call "insulin," lowered the level of sugar in the blood of several diabetic dogs. These favourable results encouraged more research and, in 1921, they were able to announce that insulin had successfully treated the dogs' diabetes. 

Life-saving discovery
 In December 1921, Macleod invited J.B. Collip, a trained biochemist, to join the research team. The team had yet to try this extract on a human. Their chance came on January 23, 1922, when Banting and Best took their extract to the Toronto General Hospital where a 14-year-old boy lay dying of diabetes. They injected the patient with an extract that Collip had made and purified from an ox pancreas. The boy was the first human diabetic to be injected with the extract. The fact that he recovered was convincing proof that the Toronto team had made a remarkable discovery.They had proved that insulin could be effective as a life-saving therapy for diabetes sufferers. As a result, Dr. Banting was named Canada's first Professor of Medical Research. By 1923, Frederick Banting, then thirty-two years old, was the most famous man in Canada. He received letters and gifts from hundreds of grateful diabetics all over the world. 
1920- Dr. Banting’s birth of idea for insulin discovery
1921- First victory, Insulin treated dog’s diabetes
1922- First clinical trials on humans with Insulin
1923- Noble prize awarded for the discovery of insulin 

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