Might we be on the verge of a new treatment for pre-menstrual syndrome based
on eau d'armpit or a new approach to fertility? US research suggests that is
a distinct possibility.
George Preti and Charles Wysocki of the Monell Chemical Senses Center, in
Philadelphia, and colleagues at the University of Pennsylvania have found
that women exposed to the secretions from a man's armpits feel less tense
and more relaxed than they otherwise would. Also, the timing of their
hormone pulses is shifted by a whiff d'homme. The findings suggest that male
pheromones could play a role in controlling the length and timing of a
woman's menstrual cycle.
Human sweat is a veritable chemical cocktail, but the sweat secreted from
the pubic regions and the armpits contains more than the average in terms of
pungent molecules. "There is nothing that says pheromones are odourless,"
says Preti, "We don't know yet whether the active molecules are several or
all the compounds which give the axillae its characteristic odour; maybe
none of these...time will tell."
Several previous studies with unwashed tee-shirts and drops of sweat dabbed
under the nose of female volunteers have hinted that underarm secretions
have potent effects on women, BO aside!
To test whether women are affected directly in terms of mood and hormone
levels by the putative male pheromones, Preti and Wysocki's team had male
volunteers wear absorbent pads under their arms. The fresh sweat was
extracted from the pads and swabbed under the noses of the female
volunteers. Half the women received extract for six hours and then a
similarly fragranced control solution for the next six hours, the other half
got the control solution first.
Nurses in the clinical research centre applied the swabs without knowing
which was which and took blood samples from the women for hormonal analyses.
The women were asked to record their mood during both control and extract
application. Preti and colleagues report their results in detail in a
forthcoming issue of the journal, Biology of Reproduction.
The researchers saw a rather startling result. During the six hour period
when extract was being applied, subjects reported feeling significantly less
tense and more relaxed than during the six hours they received control
solution. In addition, the researchers' analyses of the blood samples
revealed that the pulsing of luteinizing hormone (LH) shifted significantly
closer to the exposure to the male underarm sweat.
Preti and Wysocki suggest that so-called primer pheromones alter the LH
pulse timing. According to the researchers, the changes in the luteinizing
hormone pulses act as indicators of the release of gonadotropin releasing
hormone (GnRH) from the hypothalamus in the women's brain. GnRH itself has a
positive influence on LH and so affects the length and timing of the
menstrual cycle, which, in turn, affects fertility.
The results reveal that male underarm sweat contains at least two pheromones
- one that acts as a modulator and another that is a primer. The latter
affects a woman's brain-hormonal system, triggering the release of hormones.
"Both effects may be caused by the same molecule(s). We just have to wait
until we do the chemical isolation to find out," Preti told us.
What chemicals will be found in the pheromone mix, the researchers are not
yet quite sure. They are, however, now carrying out a detailed analysis of
male underarm sweat to try and identify the active components. Once they
have found them, it might not be too long before some entrepreneur picks up
on the idea and we see adverts in the "lads' mags" for an anti-PMS spray!