Metabolism of synthetic progestational compounds in humans.

Abstract

To study the metabolism of synthetic progestins small groups of women received i.v. injections of carbon-14 norgestrel norethisterone lynestrol and progesterone cyclopentyl enol ether or tritiated Farlutal or Provera. Two men received oral norgestrel. For each of the progestens only about half the dose was recovered in the urine. Only small amounts of the metabolites were recovered in the non-conjugated form. The studies showed differences between the metabolism of different progestins. Progesterone cyclopentyl enol ether and Farlutal were excreted more rapidly than the 17-alpha-ethynyl steroids. The 17-alpha-ethynyl compounds were excreted at different rates and produced different metabolites. A discussion of specific metabolic pathways is presented.