# Changes in the Odor Quality of Androstadienone During Exposure-Induced Sensitization **URL:** \ **Category:** Studies & Abstracts\ **Created:** [January 31, 2010, 1:47am UTC](https://pheromonetalk.com/t/changes-in-the-odor-quality-of-androstadienone-during-exposure-induced-sensitization/35837 "2010-01-31T01:47:56Z")\ **Posts on this page:** 1\ **Showing post:** 1
**Author:** ![Domnk](https://sea2.discourse-cdn.com/flex016/user_avatar/pheromonetalk.com/domnk/32/2269_2.png) [@Domnk](https://pheromonetalk.com/u/Domnk)\ **Post date:** [January 31, 2010, 1:47am UTC](https://pheromonetalk.com/t/changes-in-the-odor-quality-of-androstadienone-during-exposure-induced-sensitization/35837/1 "2010-01-31T01:47:56Z")
**Changes in the Odor Quality of Androstadienone During Exposure-Induced Sensitization** **Tim J.C. Jacob, Liwei Wang, Sajjida Jaffer and Sara McPhee** School of Biosciences, Cardiff University, Cardiff CF10 3US, UK \*Correspondence to be sent to: Tim J.C. Jacob, School of Biosciences, Cardiff University, Cardiff CF10 3US, UK. e-mail: [jacob@cardiff.ac.uk](mailto:jacob@cardiff.ac.uk) \*\*\*Abstract \*\* Androstadienone is a steroid found in human sweat and other secretions. It has been widely proposed as a candidate for a human [pheromone](https://a314.com/). As an odorant it possesses some unique properties. Here we demonstrate that, firstly, there is a very wide range of thresholds in the human population, and they are not normally distributed. Secondly, repetitive exposure causes a decrease in detection threshold of more than four orders of magnitude, and thirdly, accompanying this sensitization process is a change in the perceived odor quality. Those with low to intermediate sensitivities ascribe to it a wide range of odor descriptors across the hedonic scale, but as these individuals become sensitized, their description changes to predominantly putrid. We propose that this change in odor quality reflects the presence of at least two receptor populations for androstadienone; a low-affinity receptor conveying pleasant odor qualities and a high-affinity receptor mediating unpleasant odor qualities. We further propose that repetitive exposure results in the increased expression of the high-affinity receptor thereby shifting the balance of perception to the negative end of the hedonic scale. [Changes in the Odor Quality of Androstadienone During Exposure-Induced Sensitization – Jacob et al. 31 (1): 3 – Chemical Senses](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3) Snippets, from Discussion… “In addition, repetitive exposure to androstadienone caused a reduction in threshold in both men and women of more than four orders of magnitude from 3.5 x 10–3 M to 0.3 x 10–6 M ([Figure 3](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#FIG3)). … These properties, in particular the large threshold range spanning four orders of magnitude, may go some way to explain the variable and sometimes contradictory results; for example, different effects on mood have been reported for androstadienone, from no effect (Bensafi _et al._, 2003[http://chemse.oxfordjournals.org/icons/fig-down.gif](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#BIB2)) to a nongender specific increase in positive stimulated mood (Jacob and McClintock, 2000[http://chemse.oxfordjournals.org/icons/fig-down.gif](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#BIB15)) which was dependent upon the gender of the experimenter (Jacob _et al._, 2001[http://chemse.oxfordjournals.org/icons/fig-down.gif](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#BIB14)) or only occurred in specific contexts (Bensafi _et al._, 2004a[http://chemse.oxfordjournals.org/icons/fig-down.gif](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#BIB1)). While some subjects may have had a very low threshold and were therefore very sensitive to a given concentration of the androstene, others, with a high threshold, may have been insensitive.” “The exposure-dependent gain in androstadienone sensitivity we found was accompanied by a change in perceived odor quality. Our selected low-sensitivity subjects described androstadienone as having a wide range of odor qualities preexposure; putrid, vegetable, woody, floral, minty, and fruity. Following exposure-induced sensitization, the only descriptors were putrid, vegetable, and woody independent of the androstadienone concentration. The qualities of floral, minty, and fruity were lost during the sensitization process. Applying Occam’s razor, this result could support the hypothesis that there are at least two odor channels; a broadly pleasant channel with floral, minty, and fruity qualities and an unpleasant channel with putrid qualities. These channels could be represented by receptors, one with a high-affinity—the putrid receptor—and the other a low-affinity receptor associated with more diffuse range of more pleasant odor qualities (Polak, 1973[http://chemse.oxfordjournals.org/icons/fig-down.gif](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#BIB23); Stevens and O’Connell, 1995[http://chemse.oxfordjournals.org/icons/fig-down.gif](http://chemse.oxfordjournals.org/cgi/content/full/31/1/3#BIB26)). As sensitivity increases, the high-affinity receptor is activated at androstadienone levels well below those necessary to activate the low-affinity receptor, and the dominant odor quality becomes putrid.” --- _[View the full topic](https://pheromonetalk.com/t/changes-in-the-odor-quality-of-androstadienone-during-exposure-induced-sensitization/35837)._