How the smell of rotten eggs makes men randy

Scientists take eight transsexuals and a whiff of hydrogen sulphide to begin making an alternative to Viagra

A malodorous gas behind the smell of rotting eggs has been found to play a key role in giving men erections. Scientists believe the discovery could lead to the development of a male impotence drug to rival Viagra.

The whiff of hydrogen sulphide – a gas not traditionally associated with lovemaking – accompanies the biological degradation of sulphur-containing substances. It also belches from the exhausts of cars fitted with catalytic converters.

A study has shown that, prior to sexual intercourse, minute quantities of hydrogen sulphide are released within the key nerve cells of the penis which control the engorgement of the male organ with blood to stiffen it.

Scientists believe that the discovery could lead to the development of a new class of drugs to combat erectile dysfunction by affecting a different biochemical pathway to the one targeted by Viagra.

The research, published in the journal Proceedings of the National Academy of Sciences, was based on experiments performed on the intact erectile tissue of eight men who had undergone sex-change surgery in a hospital in Italy.

"We found that hydrogen sulphide is involved in human penile erection. That was proved in this study," said Professor Giuseppe Cirino, of the University of Naples Federico II.

"Of course, the hydrogen sulphide pathway represents a new therapeutic target for erectile dysfunction and it should be possible in future to develop drugs that either deliver hydrogen sulphide or that control the hydrogen sulphide production," Professor Cirino said.

The discovery that hydrogen sulphide gas helps penile erection mirrors the earlier discovery that another gas, nitric oxide, is involved in a similar biochemical process. That led to Viagra being used as an anti-impotence drug.

The release of nitric oxide at the nerve endings close to the blood vessels of the penis controls the human erection. By relaxing those blood vessels, blood flows into the penis and collects in special cavities, the corpus cavernosum, causing the organ to swell into an erection.

Viagra works on that biochemical pathway by stimulating the flow of blood into the penis while decreasing the flow out of the organ – maintaining an erection that might otherwise dissipate quickly or not happen at all.

Both hydrogen sulphide and nitric oxide work as "cell mediators", communicating signals between the cells that control the flow of blood within the arteries and veins. When released, the gases cause certain muscle cells to relax, allowing blood to flow more freely into the penis, leading to an erection. "Hydrogen sulphide, like nitric oxide, was best known as a toxic pollutant until recent years, when it has been proposed to be a gaseous neurotransmitter," Professor Cirino and his colleagues said.

"These observations may help to unravel the complex mechanisms underlying the patho-physiology of human penile erection and may lead to the development of therapeutic approaches in the treatment of erectile dysfunction and sexual arousal disorders."

It is estimated that about half of all men who are aged between 40 and 70 have suffered at some stage from erectile dysfunction, which is often a symptom of a wider disorder of the circulatory system, such as diabetes or heart disease.

About one third of men with erectile dysfunction do not respond to Viagra, and it is those men that Professor Cirino said may benefit from the development of a drug targeted at hydrogen sulphide rather than nitric oxide.

Suggested Topics
Start your day with The Independent, sign up for daily news emails
PROMOTED VIDEO
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Tradewind Recruitment: English Teacher

Negotiable: Tradewind Recruitment: This post arises as a result of the need to...

Tradewind Recruitment: Class Teacher Required ASAP In Uminster

£120 - £150 per annum: Tradewind Recruitment: I am recruiting on instruction o...

Ashdown Group: Head of Finance - Financial Director - London - £70,000

£70000 per annum: Ashdown Group: Head of Finance - Financial Controller - Fina...

Ashdown Group: Marketing Executive - Wimbledon, SW London

£24000 - £28000 per annum + benefits: Ashdown Group: Marketing Executive - Wim...

Day In a Page

Greece elections: In times like these, the EU has far more dangerous adversaries than Syriza

Greece elections

In times like these, the EU has far more dangerous adversaries than Syriza, says Patrick Cockburn
Holocaust Memorial Day: Nazi victims remembered as spectre of prejudice reappears

Holocaust Memorial Day

Nazi victims remembered as spectre of prejudice reappears over Europe
Fortitude and the Arctic attraction: Our fascination with the last great wilderness

Magnetic north

The Arctic has always exerted a pull, from Greek myth to new thriller Fortitude. Gerard Gilbert considers what's behind our fascination with the last great wilderness
Homeless Veterans appeal: Homeless in Wales can find inspiration from Daniel’s story

Homeless Veterans appeal

Homeless in Wales can find inspiration from Daniel’s story
Front National family feud? Marine Le Pen and her relatives clash over French far-right party's response to Paris terror attacks

Front National family feud?

Marine Le Pen and her relatives clash over French far-right party's response to Paris terror attacks
Pot of gold: tasting the world’s most expensive tea

Pot of gold

Tasting the world’s most expensive tea
10 best wildlife-watching experiences: From hen harriers to porpoises

From hen harriers to porpoises: 10 best wildlife-watching experiences

While many of Britain's birds have flown south for the winter, it's still a great time to get outside for a spot of twitching
Nick Easter: 'I don’t want just to hold tackle bags, I want to be out there'

'I don’t want just to hold tackle bags, I want to be out there'

Nick Easter targeting World Cup place after England recall
DSK, Dodo the Pimp, and the Carlton Hotel

The inside track on France's trial of the year

Dominique Strauss-Kahn, Dodo the Pimp, and the Carlton Hotel:
As provocative now as they ever were

Sarah Kane season

Why her plays are as provocative now as when they were written
Murder of Japanese hostage has grim echoes of a killing in Iraq 11 years ago

Murder of Japanese hostage has grim echoes of another killing

Japanese mood was against what was seen as irresponsible trips to a vicious war zone
Syria crisis: Celebrities call on David Cameron to take more refugees as one young mother tells of torture by Assad regime

Celebrities call on David Cameron to take more Syrian refugees

One young mother tells of torture by Assad regime
The enemy within: People who hear voices in their heads are being encouraged to talk back – with promising results

The enemy within

People who hear voices in their heads are being encouraged to talk back
'In Auschwitz you got used to anything'

'In Auschwitz you got used to anything'

Survivors of the Nazi concentration camp remember its horror, 70 years on
Autumn/winter menswear 2015: The uniforms that make up modern life come to the fore

Autumn/winter menswear 2015

The uniforms that make up modern life come to the fore