Live from AChemS – More on Sperm & Lily of the Valley

One of the advantages of a scientific conference is that you hear results straight from the horse’s mouth. Two weeks ago I wrote about the discovery of the first molecule to which men are more sensitive than women. It’s called bourgeonal and its odor character resembles lily of the valley. Two other remarkable facts about bourgeonal: it is extremely attractive to human sperm and it activates olfactory receptor OR1D2 which is expressed in sperm cells as well as the human nose.

In a comment, Carmencanada at GrainDeMusc said:

Lily of the valley is not a smell I would have associated with human reproduction. Does that mean Diorissimo and the like would attract the, hm, hm, little fellows?

I too was puzzled by why an intensely floral odor would have a role in mammalian reproduction.

At this evening’s poster session Matthias Laska, a co-author of the new paper, presented his study and I got a chance to ask him about bourgeonal. I learned a few new things.

According to Laska, bourgeonal does not occur in the female reproductive tract or anywhere else in nature for that matter. The German scientist Hanns Hatt discovered that bourgeonal activates testicular odor receptors; he and his team published the results in Science in 2003. They were using a cocktail of 100 natural and synthetic odorants to screen for receptor activation and bourgeonal was one of the hundred.

So, yes Carmencanada, your suspicions were correct. There’s no biological logic to bourgeonal’s potency as a sperm attractant. (In the original post I took the fact that it works in laboratory experiments to mean it is naturally released by the egg; sorry about that.) There may, in fact, be other odors even more effective at attracting sperm than bourgeonal—we just haven’t found them yet.

Laska also reminded me that Hatt had applied for a patent on the human odor receptor in question as well as molecules that stimulate or inhibit it. Claim 23 of the patent is for medical applications involving contraception or fertility enhancement. Lily of the valley—coming soon to a fertility clinic near you! 

Hatt has become something of an evangelist for the fundamental biological role of bourgeonal in human evolution. He recently published a book (available only in German) called The lily of the valley phenomenon: All about smell and how it affects our lives.

And that, boyz & girlz, is why it’s worth going to poster sessions.