Changes in the Odor Quality of Androstadienone During Exposure-Induced Sensitization http://chemse.oxfordjournals.org/cgi/content/full/31/1/3 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 t...