New Compounds with Progestational Activity: A Review

For some time steroid chemists have known that small chemical changes in steroid molecules may have profound effects on the biological activity of a compound. For example, a double bond inserted in the cortisone molecule greatly increases its biological activity as a-1, cortisone (meticorten). Likewise, removal of a methyl group from progesterone increases its biological activity, e.g., norprogesterone (Nor-signifying that something has been removed). In 1954 a group of investigators decided to try to increase the progestational activity of ethinyl testosterone (pregneninolone), a known potent oral progestogen, by removing this same methyl group. They succeeded in synthesizing this compound and a closely related one.' These compounds are known as the 19-nortestosterones (testosterone with a methyl group removed from the 19 position). Early evaluation of these compounds disclosed that the predicted increase in progestational activity was present.'1 Since 1954 a considerable amount of pertinent information has been published concerning these products. It is the purpose of this paper to review the literature on these preparations and to summarize the pharmacological and physiological findings to date. There are four compounds to be considered: