‘When scientists first discovered the insulin secretion effects of gut hormone GLP-1 in the 1980s, it seemed like the automatic gateway toward a landmark diabetes treatment. GLP-1, or glucagon-like peptide-1, slows digestion, signals the pancreas to release insulin, and even makes you feel full after a meal. If that peptide could be turned into a medication, experts theorized, GLP-1 could revolutionize pharmaceuticals..

But there was one major problem stumping researchers: GLP-1 lasted mere minutes in the body. Bodily hormones quickly break down both naturally produced and synthetic GLP-1, and that left drug developers unable to determine if a consistent dose of the peptide could effectively regulate insulin. It seemed, at the time, that GLP-1 was the miracle hormone that vanished too fast in the body to even be useful as a medication.

What GLP-1 lacked, however, is what another peptide had.

Enter exendin-4, composed of 39 amino acids and a close match to the sequence of GLP-1. As told in this Popular Mechanics feature, researcher Jean-Pierre Raufman and endocrinologist John Eng discovered exendin-4 in the 1990s in the most unlikely of places: the venom of the thick-skinned Gila monster. Turns out, the venom proved useful as a blood sugar and appetite regulator. Raufman’s years of studying animal toxins led to the uncovering of exendin-4 and eventual production of type 2 diabetes drug Byetta—and it’s a breakthrough that kick-started the entire GLP-1 drug industry.’ (Ashley Tysiac via Popular Mechanics)