Kiwis ponder fertility puzzle's next piece

Discovered 10 years ago, the small protein is considered the most important factor in how our brains regulate fertility. Photo / Thinkstock

Otago scientists trying to work out how to use breakthrough find.

Kiwi scientists who helped to pinpoint the "microchip" in our brain that can control fertility are now working on the next crucial piece in the puzzle - how to influence it.

A landmark study, published in leading international journal Nature Communications last year, revealed the cell in our brain where the process that results in fertility is triggered.

It is estimated up to 20 per cent of New Zealand couples are infertile, and about one-third of all cases of infertility in women involve disorders in the area of brain signalling to the ovaries.

The research, by Otago University's Centre for Neuroendocrinology, was a large leap toward better understanding a key player in this process - the ovulation-triggering protein known as kisspeptin.

Discovered 10 years ago, the small protein is considered the most important factor in how our brains regulate fertility.

In September, scientists revealed the cellular location of signalling between kisspeptin and its receptor, which together trigger a cascade of biochemical changes through the body that enables fertility.

"Our new understanding of the exact mechanism by which kisspeptin acts as a master controller of reproduction is an exciting breakthrough which opens up avenues for tackling what is often a heart-breaking issue," Otago neuroscientist Professor Allan Herbison said.

"The key thing now is to understand what kisspeptin does to that neuron when it activates the receptor - what are the signalling pathways, and how does it turn the neuron on?"

As well as influencing the processes behind fertility, solving the puzzle could also lead to a new contraceptive that was selective and did not affect other tissues in the body, he said.

"It leads to the ability to turn on the system in women who are infertile and get ovulation.

"The alternative scenario always is if you define the pathway, the step-by-step mechanism that activates this neuron, then you can also design things that do the opposite. In other words, if you can turn it off, then you have a new contraceptive."

Professor Herbison said the discovery of kisspeptin in Hershey, Pennsylvania - the home of Hershey's Kisses chocolates, hence its name - had been "hugely important" in understanding the switch that turned on fertility.

"It's become an incredible tool for activating a whole system that is not up and going any more."

In trials since, mice had regained fertility when kisspeptin was injected, the protein reactivating their fertility system.

A small number of clinical trials on humans have begun to examine this effect in women.

That the fertility process began in the brain came as a surprise to many, but in both sexes, it was where the newly discovered kisspeptin reaction took place.

Kisspeptin: the microchip of fertility

• The accidental discovery of kisspeptin a decade ago proved a major leap in understanding how our body works.

• The protein, encoded by the KISS1 gene in humans, triggers a cascade of biochemical changes that lead to fertility and puberty.

• Scientists have suggested other important medical applications, namely using it to block production of hormones that nurture tumours in breast
and prostate cancers.

• Otago University researchers helped to establish the cell in the brain where kisspeptin activates a sequence of events that enables fertility.