Platypus venom could hold key to diabetes treatment

Platypus venom could hold key to diabetes treatment
The Taronga Zoo is celebrating its first successful Echidna births in nearly 30 years.
Photo: AFP

It is an egg-laying, duck-billed, beaver-tailed marvel, and the pride of Australia.

Now the platypus, one of nature's most unlikely animals, could pave the way for better treatments for diabetics.

Researchers have discovered remarkable evolutionary changes to insulin regulation in two of Australia's most iconic native animal species - the platypus and the echidna - which could lead to new treatments for Type 2 diabetes in people, according to the University of Adelaide.

The findings, published in the journal Scientific Reports, reveal that the same hormone produced in the gut of the platypus to regulate blood glucose is also - surprisingly - produced in its venom.

The research was led by Professor Frank Grutzner of the University of Adelaide and Associate Professor Briony Forbes of 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, said the university in a statement.

GLP-1 typically degrades within minutes. In people with Type 2 diabetes, the short stimulus triggered by GLP-1 is not sufficient to maintain a proper blood sugar balance.

So medication that includes a longer-lasting form of the hormone is needed to help provide an extended release of insulin.

"Our research team has discovered that monotremes (egg-laying mammals) - our iconic platypus and echidna - have evolved changes in the hormone GLP-1 that make it resistant to the rapid degradation normally seen in humans," said ProfGrutzner from the University of Adelaide's School of Biological Sciences and the Robinson Research Institute.

"We've 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."

The platypus produces a powerful venom during breeding season, which is used in the competition among males for females.

Said Prof Forbes, from Flinders University's School of Medicine: "We've 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."

She added: "The 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."

Prof Grutzner added: "This is an amazing example of how millions of years of evolution can shape molecules and optimise their function.

"These 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."

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 are no such spurs on echidnas.

"The lack of a spur on the echidna remains an evolutionary mystery, but the fact that both the platypus and the echidna have evolved the same long-lasting form of the hormone GLP-1 is in itself a very exciting finding," said Prof Grutzner.


This article was first published on Dec 02, 2016.
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