Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Unisex contraceptive tailed

11.10.2001


Channel stopping makes sperm swim slowly and aimlessly.
© SPL


Sperm go slow without a crucial protein.

The discovery of a protein that is crucial to sperm swimming in mice could lead to new male or female contraceptives or fertility treatments.

The protein forms a channel through the membrane of the sperm tail. It controls the inflow of calcium ions that trigger swimming.



All humans have the gene that encodes the channel, but it is switched on only in sperm cells. This would lessen the risk of side-effects from any channel-blocking contraceptive, for example.

"We think it’s going to be very useful for the development of male contraceptives," says Dejian Ren of Harvard Medical School in Boston1.

Ren’s team created mutant mice lacking the ion channel; all were sterile. These animals’ sluggish sperm move at about one-third of normal speed. The sperm also lack their normal counterparts’ sense of direction.

Sperm without the channel are incapable of making a violent whiplash movement, called hypermotility. Sperm turn hypermotile inside a female - possibly in response to a chemical signal from her - just before fertilization.

This turn of speed seems to enable a sperm to burst into the egg. Mutant sperm are too feeble to do this; they can fertilize an egg only if its outer layer is removed.

"Calcium has long been known to be very important in sperm function, but the details have been very elusive," says cell biologist David Garbers of the University of Texas Southwestern Medical Centre in Dallas. Much remains to be worked out about how the channel works, but the story so far is "all pretty cool", he says.

Defective calcium channels might be a cause of human male sterility. The same could be true for other ion channels in sperm, says Susan Benoff of North Shore University Hospital in Manhasset, New York.

Benhoff is developing contraceptives that target calcium channels in the heads of sperm. "Most male contraceptives in the pipeline are based on hormonal methods," she says. The effects of these may be hard to reverse: "Sperm count may not get back up to the usual level," says Benhoff. Ion-channel blockers could avoid these pitfalls.

Worldwide, the market for oral contraceptives was worth almost US$4 billion last year. The demand for a male pill would be "phenomenal", says Benoff. "Surveys show that men would be as willing as women to use oral contraception if it was convenient. I get phone calls every week from people wanting to take part in trials."

Potential male contraceptives have been overhyped in the past, warns Paul Wassarman, who studies fertilization at Mount Sinai School of Medicine in New York City. "Everyone who’s able to prevent fertilization thinks they have a target for contraception. Whether it’s realistic or not remains to be seen."

References
  1. Ren, D. et al. A sperm ion channel required for sperm motility and male fertility. Nature, 413, 603 - 609, (2001).


JOHN WHITFIELD | Nature News Service
Further information:
http://www.nature.com/nsu/011011/011011-10.html

More articles from Health and Medicine:

nachricht Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State

nachricht NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Cloud Formation: How Feldspar Acts as Ice Nucleus

09.12.2016 | Life Sciences

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>