Abstract
Summary
The metrotropic activity of a series of C-21 haloprogestins was assayed in the Clauberg, uterine carbonic anhydrase, and intrauterine (McGinty) assays. C-21 Fluorination of both 17α-acetoxy-progesterone and 6α-methyl-17α-acetoxyprogesterone resulted in a marked increase in oral potency of both substances; subcutaneously, potency was unaltered by this structural modification. Upon local instillation of these 21-halogenated progesterone derivatives, decreased potency was observed as atomic weight of substituted halogen increased. 21-Fluoro-17-acetoxyprogesterone failed to increase progestational potency in the intrauterine assay thus differing from other 21-fluoroprogesterones. The most potent metrotropic agent tested was 6α-methyl-17α-acetoxy-21-fluoroprogesterone. Orally, it was twice as potent as its non-fluorinated analogue and 10 times more potent than subcutaneously administered progesterone. It was 50 times more potent than progesterone when both were given subcutaneously and about 50 times more potent than progesterone when given locally.
Get full access to this article
View all access options for this article.