Egg May Lure Sperm By "Smell"

Finding Could Lead to New Fertility Treatments, Birth Control Methods

From the WebMD Archives

March 27, 2003 -- When everything's right, sperm cells may be able to "smell" an egg, causing them to make a beeline for the target. It's a new discovery, one that could lead to advances in contraception and fertility treatments.

A new study, appearing in the latest issue of the journal Science, explores the concept of "chemo-attraction."

A group of German and U.S. researchers report that the activation of an "odorant receptor" -- found on the surface of sperm cells -- seems to trigger a series of events that leads the sperm to not only move towards a sperm-attracting substance called "bourgeonal," but also to move there more quickly.

Ideally, the object of the sperm's destination would be the egg, but the scientists do not yet know if the egg itself produces some sperm-attracting compound similar to bourgeonal -- or if some other part of the female reproductive tract makes the chemical that may bind to the sperm's receptor.

Researchers have also identified a potential problem to fertilization -- a compound called "undecanal" -- that appears to block the effect of bourgeonal. It seems to inhibit the sperm's natural attraction to this compound.

The finding could lead to new forms of contraception, or to new fertility treatments, by manipulating the signals sent between sperm and egg, writes lead author Marc Spehr, of Ruhr University Bochum in Germany.

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SOURCES: News release, American Association for the Advancement of Science. Science, March 28, 2003.
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