Scientists from the University of Leicester have made a breakthrough in male fertility research that could, eventually, lead to the development of a male fertility pill.

The scientists, Drs Richard Evans, Catrin Pritchard et al, have discovered a way of restricting the delivery of sperm from the testes thereby making semen virtually sperm free.

The potential is huge for fertility treatments as the research also suggests ways of increasing the flow of sperm, thereby increasing fecundity.

The breakthrough, announced in the science magazine Nature, came after the researchers found that, by targeting a gene in mice, there was a 90% drop in fertility rate. The mice suffered no other side effect other than a small rise in blood pressure. They continued to copulate as normal - with only 13% of matings resulting in pregnancy compared to the usual 100%.

Scientists believe the research, funded by the Medical Research Council and Wellcome Trust, is a step forward because it does not interfere with male sperm production - only its transfer. Effectively, they have discovered a 'sperm tap'.

The sperm is produced as normal in the testes, but the transfer of this sperm into the semen is restricted so that it remains virtually sperm free.

Evans and Pritchard said: "Sperm are made in the testes and transferred out of the body through a tube called the vas deferens - the tube that is cut in a vasectomy. Contractions in the smooth muscles that line this tube help to send the sperm on their way.

"We have found a way of targeting this muscle contractions by looking at how the gene for a protein called the P2X1 receptor is central in regulating male fertility.

"Without the P2X1 receptor, contractions of vas deferens are markedly reduced and semen is almost sperm free."

Evans and Pritchard said the role for the P2X1 receptor in sperm transfer and not sperm formation makes it ideal for testing possible male contraception pills because it prevents fertilisation without affecting other aspects of 'maleness.' Such pills would act in the same way as a reversible vasectomy.

And because the P2X1 receptor could be specifically targeted, it could help to increase the flow of sperm and prove beneficial for infertile men.

However the scientists say that more research needs to be done and the development of the male contraception pill based on this research is still some years away.

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Information supplied by: Barbara Whiteman
Last updated: 06 January 2000 15:53
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