In Australia and Tasmania, there is a unique semi-aquatic mammal called the duck-billed platypus. The males have a venomous spur on their hind feet that they use to defend themselves. The venom can kill small animals and cause intense pain to humans. The pain has been compared to hundreds of hornet stings. The spurs are attached to venom-secreting glands which are especially active during the mating season. It is thought that they help males compete for mates. The venom contains a cocktail of different molecules and scientists have found that one of those molecules could lead to a new treatment for Type 2 diabetes.
The platypus is an unusual mammal about half the size of a house cat. They have sleek furry bodies, leathery paddle-shaped tails and webbed feet. The front end is also unusual. With a flat bill that is flexible and rubbery but lacks teeth, the bill is full of sensors that help the platypus find food underwater. Females also lay eggs like a reptile. They live close to water, digging burrows deep into riverbanks or under rock ledges, roots or debris. They sleep during the day and hunt for worms, crustaceans, and insects at dusk or at night.
One of the components of platypus venom is a molecule called glucagon-like peptide-1 (GLP-1). GLP-1 is found in humans and other mammals, but it is not usually associated with a venom. In humans, GLP-1 is important in regulating the release of insulin, a hormone that regulates blood sugar. GLP-1 is secreted by cells in the intestine after you eat a meal. It causes the intestine to start moving food through the digestive system, stops the secretion of stomach acid and sends a signal to the nervous system that you are full. In the pancreas, GLP-1 expands the cells that produce insulin, increases the release of insulin and inhibits secretion of glucagon, which raises blood sugar and works against insulin.
Drugs based on GLP-1 can help people with Type 2 diabetes because their bodies do not use insulin effectively. There are drugs already on the market based on increasing GLP-1 activity. GLP-1 breaks down in less than two minutes so it cannot be used to treat diabetes. Drugs that act like GLP-1 have been developed to produce the same results as GLP-1, including releasing more insulin. These drugs can last up to several days depending on the drug and the formulation. Other benefits from using GLP-1-like drugs may include small reductions in blood pressure and decreased inflammation.
The human GLP-1 molecule degrades quickly but the platypus GLP-1 is more stable. If scientists could determine why the platypus GLP-1 is so much more stable than the human one then they could engineer a human GLP-1 to be similarly stable. The platypus GLP-1 could be used to treat Type 2 diabetes and with fewer side effects than current drugs. Just like human insulin is currently available in short-acting and long-acting forms, GLP-1 could be modified to last for varying lengths of time.
Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at www.medicaldiscoverynews.com.