Read more: 鈥�Drugs with bite: The healing powers of venoms鈥�
DRUG: Exenatide (Byetta)
SOURCE: Gila monster
CONDITION: Type 2 diabetes
A bite from a gila monster will really mess with your metabolism. Fortunately these lizards, found in the deserts of the south-west US, are large and lumbering and most humans can easily outpace them. Nevertheless, each year a handful of people do get close enough to discover that the gila monster鈥檚 bite delivers a painful cocktail of chemicals that causes nausea, fever and faintness 鈥� and can even induce a heart attack.
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However, within the venom lies a very useful compound. Called exendin 4, it triggers one of the body鈥檚 insulin-releasing pathways. This effect makes it ideal for treating type 2 diabetes, a condition in which insufficient insulin is produced to keep glucose levels in check. A synthetic version of exendin 4, called exenatide, was approved as an anti-diabetes drug by the US Food and Drug Administration in 2005. Now the compound is being investigated for its anti-obesity properties as well, since it also slows stomach emptying, reinforcing feelings of fullness after eating.
Until around five years ago, the gila monster was thought to be one of just two venomous lizards 鈥� the other being the closely related beaded lizard found in nearby Mexico. We now know that lizards and snakes share a common venomous ancestor, and that many lizards 鈥� from iguanas to komodo dragons 鈥� which were never suspected of being venomous, come equipped with venom glands ().
鈥淯ntil recently the gila monster was thought to be one of just two venomous lizards鈥�
Research into lizard venom has barely begun, so it may be a while before any other lizard-based medicine hits the pharmacy. But the wait could be worth it, says Bryan Fry at the University of Queensland in Brisbane, Australia, who has led the work on lizard toxin evolution. 鈥淚f you want to find something useful, then the more novel the venomous animal, the more novel its venom.鈥� And that gives the best drug leads, he says. 鈥淚 think it is one of the strongest arguments we have for preserving biodiversity.鈥�
