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Instructions,
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Gender
- Specific Induction of Enhanced Sensitivity to Odors This brief communication explores the
plausible explanation that sex hormones mediate differences in sensitivity. The authors demonstrate significant changes in olfactory
activity occurring during repeated test exposures to several odorants among
women with average baseline sensitivity to these components. The increased sensitivity, averaging five orders of
magnitude, was observed only among females of the reproductive age,and not among
men. In a second test, the same six
subjects and six naïve subjects were tested with repeated exposures with
benzaldehyde, and 2 odorants, 5 methylfurfuryl (cherry odor) and isoamyl acetate
(banana odor) to serve as controls. Sensitivity
to benzaldehyde increased substantially for both naïve and experienced women.
The females showed a slight cross facilitation to 5-methylfurfuryl, but
no change in threshold to isoamyl acetate.
The results demonstrated that the sensitivity increase associated with
repeated threshold testing on women was replicable and odorant specific.
This supports the hypothesis that the effects were not due to practice. These investigators also tested 10 new
participants (5 male and 5 female) using citralva (lemon-orange odor) and
benzalehyde as the control. Citralva
thresholds decreased markedly for women with repeated testing, but the
thresholds were unchanged for men. There
were no changes in the sensitivity to benzaldehyde in either gender.
These results demonstrated that sensitization may be induced with
different compounds and initial sensitivity to a given component was not
required. An
additional study by these investigators, compared the olfactory activity of
females whose average estrogen levels were presumed to be substantially lower
than the females of the original study, 4 premenarche girls (age 8-10), 4 post
menopausal women (ages 49-61) not taking hormone replacement therapy and an
equal number of age matched men and boys. The
results showed that the sensitivity to benzaldehyde did not change with repeated
exposures for either boys or girls. Similarly, there were no significant gender differences
across sessions in the older female group (post menopausal). These authors suggest the possibility that the amounts of
female sex hormones present between onset of menarche and menopause have a role
in enabling exposure induced increases in odor sensitivity.
The authors further speculate that, as a negative consequence, this
phenomenon may account for the greater prevalence of odor-related environmental
complaints from females namely, sick building syndrome or chemical intolerance
syndromes. Source: Dalton, P. Doolittle, N., and Breslin, P.A. 2002. Gender-specific induction of enhanced sensitivity to odors. Nature neuroscience 5 (3):199-200. By: Arlene Weiss, MS, DABT, Epidemiology/Environmental Health Consulting Editor
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