Asparagus rears its lovely head

In case you weren't aware, spargel, the white asparagus is now coming on the market in Europe. If you've never had it, you have missed one of the side dishes of the gods.



Parental Advisory: The material in the following post has been deemed offensive to the tender EAR , EYE, o.k. to the tender NOSE.

We have all been intrigued by Rush Limbaugh and his "escapades." As of this writing, he has been enscounced in a parole program where he will have his urine tested on a regular basis and at random for the noxious hillbilly heroin (and other "substances"). Poor Rush, to have to descend to the level of the plebian.

Well, anyway, Mr. TBogg has instituted Operation Micturition wherein recruits will send Mr. Limberger urine cups filled with "clean" stuff in case he needs to slip something in. Anyway, you can go here to collect the details.

The story begins to unfold in the Comments of TBogg's post:

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Take my advice from my time in the Navy...

EAT LOTS OF ASPARAGUS before dropping your sample!

I used to work as a printer in the Navy, and was usually the one to print-up the urinalysis logs, therefore, getting a 24-hour heads-up. I would eat BUNCHES of asparagus for breakfast, before going into work.

If you haven't noticed, asparagus makes the urine smell especially noxious, due to an ezyme in the vegetable. I never did drugs while in the Navy, but, I had no tolerance or appreciation for the judging of my work quality by the contents of my urine... So, this was my little way of getting even.
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Oh... and send it via a slower boat... a few days in hot mail trucks should amplify the effect nicely.
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And

The asparagus bit is a myth, don't waste your time. And remember, Rush, it's better to be pissed off than pissed on...
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The asparagus thing isn't a myth per se -- asparagus gives me smelly pee. But it's a genetic thing, so if you don't have the gene that makes your pee smelly after you eat asparagus, you can eat all the asparagus in the world and it won't do a damn thing.(emphasis added)
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We have an asparagus-eating cat, who must also have the critical enzyme in her system. Maybe Rush would like some of that.

Asparagus eating cat!! Sweet Holy Jezus. Bear with me, it really does get better:

I thought the asparagus gene goes the other way: if you have it, you can smell asparagus in urine.
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There apparently is some debate as to whether the "asparagus pee" smell originates in the urine or in the nose:
http://store.yahoo.net/nmcs/asparagus.html
I think this may be a case for the Mythbusters.
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Wikipedia claims that the asparagus pee issue is genetic and unrelated in both production and detection:
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Studies showed that about 40% of the test subjects displayed this characteristic smell; and a similar percentage of people are able to smell the odor once it is produced. There does not seem to be any correlation between peoples' production and detection of the smell.

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i'd take wikipedia's entry with skepticism if i were you. they have people do the entries, but the review/editing of them leaves a lot to be desired....

O.K., where were we:

Dear Dr. Dave and Dr. Dee,

My boyfriend's urine smelled awful after eating asparagus. We both ate the same meal, but my urine was fine. My boyfriend says that everyone's urine smells after eating asparagus, and since mine doesn't, then I'm the strange one, not him. No one in my family has ever had urine odor from eating anything. Is he right, or might he have a problem?

Signed,

Worried

"It's the same sulfur group that makes skunks smell," said Barbara Hodges, a dietician with Boston University's nutrition clinic, the Evans Nutrition Group. (emphasis added.)

According to the Dictionary of Medical Syndromes, which includes an entry on the urinary excretion of odoriferous components of asparagus: "The syndrome does not have any pathological significance."

The Michigan Asparagus Advisory Board

Thank you MAAB. Now to the nitty gritty, first we have the nose:

And in the nose, we have the olfactory receptors:

Rather than binding to specific ligands like most receptors, olfactory receptors bind to structures on odor molecules. Once the odorant has bound to the odor receptor, the receptor activates the attached G protein on the inside of the olfactory receptor neuron. The G protein in turn activates adenylate cyclase which converts ATP to cyclic AMP(cAMP)(No, my friends, that is not the G-Spot, the G-protein). The cAMP opens ion channels which allow sodium ions into the cell, depolarizing the olfactory receptor neuron and beginning an action potential which carries the information to the brain.

Now here comes the puzzle. I had always been led to believe that we had 10,000 out of 90,000 genes for smell. It turns out that we don't have anywhere near as many. According to a paper by Crasto et al there have been only about 350 olfactory genes identified in the human genome. Many of the supposed olfactory genes are pseudogenes and may be associated with evolution (?drift). In any case, the genes code for the receptors in the olfactory nerves as per this diagram:

Individual olfactory receptor neurons die out and are replaced approximately every 40 days, so that there is a constant turnover of neurons in the olfactory epithelium. These cells are replaced by stem cells residing in the olfactory epithelium. Most neurons in other parts of the nervous system cannot be replaced, so research focusing on how stem cells differentiate into olfactory sensory neurons could lead to the use of these stem cells to replace damaged or degenerated neurons in the brain, spinal cord, or other parts of the nervous system.

WOW! STEM CELLS. Who would ever have guessed. You see, Rush, they're everywhere.

Now for the Cicero Hypothesis: There is no doubt in my mind that one of the olfactory receptors is for attar of asparagus. But we still don't know why some people have the gene and some don't. Could be a pseudogene thing. Who knows?

So, in summary, if Mr. Rush wants to beat the rap, then he should eat plenty of asparagus.

And, tell them Sergio sent you.