Platypus venom could hold key to diabetes treatment
Australian researchers have discovered remarkable evolutionary changes to insulin regulation in two of the nation鈥檚 most iconic native animal species 鈥 the platypus and the echidna 鈥 which could pave the way for new treatments for type 2 diabetes in humans.
The findings, now published in the Nature journal Scientific Reports, reveal that the same hormone produced in the gut of the platypus to regulate blood glucose is also surprisingly produced in their venom.
The research is led by Professor Frank Gru虉tzner at the 成人大片 and Associate Professor Briony Forbes at Flinders University.
The hormone, known as glucagon-like peptide-1 (GLP-1), is normally secreted in the gut of both humans and animals, stimulating the release of insulin to lower blood glucose.
But GLP-1 typically degrades within minutes.
In people with type 2 diabetes, the short stimulus triggered by GLP-1 isn鈥檛 sufficient to maintain a proper blood sugar balance. As a result, medication that includes a longer lasting form of the hormone is needed to help provide an extended release of insulin.
鈥淥ur research team has discovered that monotremes 鈥 our iconic platypus and echidna 鈥 have evolved changes in the hormone GLP-1 that make it resistant to the rapid degradation normally seen in humans,鈥 says co-lead author Professor Frank Gru虉tzner, from the 成人大片鈥檚 School of Biological Sciences and the Robinson Research Institute.
鈥淲e鈥檝e found that GLP-1 is degraded in monotremes by a completely different mechanism. Further analysis of the genetics of monotremes reveals that there seems to be a kind of molecular warfare going on between the function of GLP-1, which is produced in the gut but surprisingly also in their venom,鈥 he says.
The platypus produces a powerful venom during breeding season, which is used in competition among males for females.
鈥淲e鈥檝e discovered conflicting functions of GLP-1 in the platypus: in the gut as a regulator of blood glucose, and in venom to fend off other platypus males during breeding season. This tug of war between the different functions has resulted in dramatic changes in the GLP-1 system,鈥 says co-lead author Associate Professor Briony Forbes, from Flinders University鈥檚 School of Medicine.
鈥淭he function in venom has most likely triggered the evolution of a stable form of GLP-1 in monotremes. Excitingly, stable GLP-1 molecules are highly desirable as potential type 2 diabetes treatments,鈥 she says.
Professor Gru虉tzner says: 鈥淭his is an amazing example of how millions of years of evolution can shape molecules and optimise their function.
鈥淭hese findings have the potential to inform diabetes treatment, one of our greatest health challenges, although exactly how we can convert this finding into a treatment will need to be the subject of future research.鈥
GLP-1 has also been discovered in the venom of echidnas. But while the platypus has spurs on its hind limbs for delivering a large amount of venom to its opponent, there is no such spur on echidnas.
鈥淭he lack of a spur on echidnas remains an evolutionary mystery, but the fact that both platypus and echidnas have evolved the same long-lasting form of the hormone GLP-1 is in itself a very exciting finding,鈥 Professor Gru虉tzner says.