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For a Few Atoms More

When the game becomes less of a game

Roald Hoffmann

Turning Wheels

The 2006 Tour de France winner, Floyd Landis, was reported to have failed a testosterone drug test. More of what was actually found in his urine in just a while. Race officials collected a sample after his comeback victory in a critical stage of bicycling's premier race. A second sample confirmed the problem, and eventually Landis's victory was disallowed. Appeals followed; as the case stands now, Landis has appealed to the Court of Arbitration for Sport to overturn the decision against him.

Testosterone is the principal male sex hormone, produced mainly where you would expect from its name. It is also made in the ovaries of females. Testosterone is an anabolic compound, so-called because it promotes the growth of tissues such as muscle and bone; testosterone is also a steroid, member of a class of molecules that gives us a continuing lesson that almost the same is not the same.

All the steroids have the same atomic framework—four all-carbon rings, fused together. Three are hexagons, the third ring going off at an angle to the other two. Fused to that last ring is a pentagon of carbon atoms. Call the rings A (6 carbons), B (6), C (6) and D (5). Testosterone has an oxygen and a hydrogen (OH) attached to ring D and two CH3 (methyl) groups, one at the juncture of rings C and D, the other at the juncture of A and B. Ring A contains a double bond and has an oxygen attached to it as well.

Testosterone is responsible for the secondary sex changes that occur in male puberty—facial and pubic hair, oily skin, body odor, all that teenage-boy stuff. But the molecule is also produced by human females, albeit in one twentieth of the amount in males. In both sexes, testosterone affects energy levels and protects against osteoporosis. Nothing is simple in the real world—only human beings want it black or white, male or female.

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