The first orally active progestin, ethisterone (pregneninolone, 17α-ethynyltestosterone or 19–norandrostane), the 17α-ethynyl analog of testosterone, was synthesized in 1938 by Hans Herloff Inhoffen, Willy Logemann, Walter Hohlweg, and Arthur Serini at Schering AG in Berlin and marketed in Germany in 1939 as Proluton C and by Schering in the U.S. in 1945 as Pranone.
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Ethisterone was also marketed in the U.S. from the 1950s into the 1960s under a variety of trade names by other pharmaceutical companies that had been members of the pre-World War II European hormone cartel (Ciba, Organon, Roussel).
In 1961, Ciba and Parke-Davis added the reported association of ethisterone and norethisterone with masculinization of external genitalia of the female fetus to the precautions section of their advertisements to physicians and physician prescribing information.
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In general, pregnane derivatives (progesterone, dydrogesterone, 17α-hydroxyprogesterone caproate, medroxyprogesterone acetate, megestrol acetate, etc.) do not virilize even in high dose; testosterone derivatives (ethisterone) and 19-nortestosterone (norethisterone, norethisterone acetate, etc.) generally virilize, but there are exceptions (e.g. norethynodrel) that do not.