 by Preston MacDougall March 24, 2005
Before I give you the answer to this question, which always appears on the final class test (covering organic chemistry and astronomy) when I teach physical science for non-science majors, a little history is in order. Fifty years ago, the first human study of the effects of a synthetic version of the hormone progesterone, taken orally, were conducted in Boston. Began late in 1954, and successfully concluded early in 1956, with little media attention, 1955 marks the realization of the regimen of taking birth control pills to maintain menstruation, but prevent ovulation. In addition to 12 female and 16 male psychiatric patients from a regional hospital, whose families signed consent forms, fifty women volunteered to take part in this historic trial. Throughout the trial the women had a normal menstruation cycle, and none of the participants ovulated. After the trial, ovulation resumed, at least for the women. Margaret Sanger founded the American Birth Control League in 1921, and it was her life-long goal to make economical, and legal, methods of birth control available to women. The Boston trial was a huge success for her, but it would not have been possible without the financial backing of Katharine McCormick, the heiress of the International Harvester fortune. McCormick, born in 1875, was unusual in her day in that she had a bachelor's degree in biology from MIT. Her faith in Sanger's vision and her faith in biochemistry, are what ultimately propelled these studies forward, eventually leading to FDA approval in 1960. One wealthy patron, however, would not have been enough to achieve Sanger's goal of an economical birth control pill. Progesterone itself had been one of the molecular tools of medical practice since the 1930's, for the treatment of certain menstrual conditions for instance, but its cost would have been prohibitive had anybody then considered it for more widespread uses. Until the 1940's, commercial progesterone was synthesized by a multi-step process beginning with cholesterol, with each step yielding diminishing returns, both materially and financially. Without a chemical short-cut to synthetic progesterone, or an artificial mimic of it (which is what eventually ended up in "the pill"), Sanger's activism and McCormick's philanthropy would have been just good intentions. This brings us back to the multiple-choice question earlier. Educated as a chemist at the University of Maryland, Russell Marker was A.B.D. (all but dissertation) when he left for industry. Among other dealings with hydrocarbons, which are chemical compounds of just hydrogen and carbon, as the name implies, Marker invented the "octane number" when he worked for Ethyl, the company. Lacking a doctorate, his return to academia, to focus on the chemistry of steroids, which add only oxygen to their atomic palette, was made possible by a research faculty position at Penn State funded by Parke-Davis. Wondering about the structures and chemical reactivity of steroid molecules, drawn with what must surely appear to be hieroglyphics to the non-chemist, in 1938 he supposed that a steroid from the sarsaparilla plant was incorrectly drawn in textbooks, and that the correct structure could transformed into progesterone with a few simple, and efficient, chemical reactions. The plant steroid is a more complicated molecule than the sought-after sex hormone, but most of the differences are at one end. So the first order of business was to chemically remove the unwanted portion of the molecule, snip, snip. Using standard organic chemistry, but in a sequence that suited the initial and final structures, Marker's plan worked like a charm in the laboratory, and is now called the Marker degradation. The only remaining problem was that the sarsaparilla plant is not well-endowed with the desired plant steroid. Marker started bio-prospecting for molecular gold mines, so to speak, and in 1941 a botany textbook held clues that pointed to a wild yam that grew in the Mexican state of Veracruz. The rest is history, but now you are one step closer to an A if you ever decide to take physical science from me. If you enjoy historical travel, you will also be able to appreciate the significance of the pair of International Historical Chemical Landmarks, one in Mexico City and one in University Park, Pennsylvania, that were erected jointly by the Mexican and American Chemical Societies. Embossed on both is "The 'Marker Degradation' and the creation of the Mexican Steroid Hormone Industry." Admission is free.
Preston MacDougall is a chemistry professor at Middle Tennessee State University. His "Chemical Eye" commentaries are featured in the Arts and Public Affairs portion of the Nashville/Murfreesboro NPR station WMOT (www.wmot.org).
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