Insulin Coin toss Secretions Commentary

Frederick Banting, Charles Herbert Best medicine

Insulin

• Claude Bernard’s methods paid off
• to help people with diabetes.
• Bernard advocated experimenting with animals.
• Experiments with dogs showed diabetes
• was a problem with the pancreas.
• Clusters of cells in the pancreas called “islets of Langerhans”
• secreted a hormone assumed
• to regulate sugar metabolism.
• But extracts from pancreas of healthy dogs
• proved to be unsuccessful therapies for dogs with diabetes.
• Frederick Banting assumed these attempts failed
• because liquids from other cells in the pancreas
• deactivated the secretions from the islets.
• Working with Charles Best, Banting tied off
• a dog’s pancreatic duct, which they knew would cause
• the pancreas to atrophe
• except for the islets.
• From these, they were able to extract a substance
• that restored the health of a diabetic dog.

Coin toss

• Banting convinced J.J.R. Macleod to let him
• use his laboratory and eleven dogs at the University
• of Toronto to experiment with the pancreas.
• Macleod assigned two medical students,
• Clark Noble and Charles Best, as lab assistants,
• but Banting wanted only one assistant at a time.
• Best won the first turn by a coin toss and Noble
• was not given a chance to take his turn because
• Banting decided to keep Best for the entire summer.

Secretions

• The pancreas has more than one kind of cell; it produces
• digestive enzymes that are needed in the small intestines,
• and its islet of Langerhans cells secrete hormones—glucagon,
• amulin, somatostatin, pancreatic polypeptide, ghrelin,
• and insulin—directly into the bloodstream.
• The insulin extracted from a dog’s atrophed pancreas
• cured a dog, but when given to a fourteen-year-old boy
• caused a severe allergic reaction. The rest of the history
• of insulin is about developing a pure source for the hormone
• to make it safe for humans.
• Today, insulin is made by genetically
• altered E. coli.
• Funny to think that insulin from a dog,
• insulin from fetal calves, synthetic insulin, or insulin
• from altered E. coli is still the same as the hormone that
• a healthy pancreas in any animal with a backbone secretes
• but that it was so hard for chemists to tune in
• this one clean
• pure
• life-saving
• hormone.