From:
http://www.erox.com/SixthSense/StoryOne.html

At first sight, it may seem odd that such similar molecules as androstenone and androstadienone would have such dramatically different effects on the female VNO. After all, their olfactory properties are quite similar, as are their electrostatic and hydrophobic binding properties. Indeed, there is evidence that both molecules interact with the same putative olfactory receptor.(13)
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13. JE Amoore, P Pelosi and LJ Forrester, Specific anosmias to 5a-androst-16-en-3-one and w-pentadecalactone: the urinous and musky primary odors, Chem Senses Flavor 2 401-425 (1977)