Retroprogesterone, also known as 9β,10α-progesterone or as 9β,10α-pregn-4-ene-3,20-dione, is a

progestin A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural female sex hormone progesterone in the body. A progestin is a '' synthetic'' progestogen. Pro ...

which was never marketed. It is a

stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms i ...

of the naturally occurring progestogen

progesterone Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...

, in which the

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atom at the 9th carbon is in the α-position (below the plane) instead of the β-position (above the plane) and the

methyl group In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ma ...

at the 10th carbon is in the β-position instead of the α-position. In other words, the atom positions at the two carbons have been reversed relative to progesterone, hence the name ''retro''progesterone. This reversal results in a "bent" configuration in which the plane of rings A and B is orientated at a 60° angle below the rings C and D. This configuration is ideal for interaction with the

progesterone receptor The progesterone receptor (PR), also known as NR3C3 or nuclear receptor subfamily 3, group C, member 3, is a protein found inside cells. It is activated by the steroid hormone progesterone. In humans, PR is encoded by a single ''PGR'' gene res ...

, with retroprogesterone binding with high affinity to this receptor. However, the configuration is not as ideal for binding to other steroid hormone receptors, and as a result, retroprogesterone derivatives have increased selectivity for the progesterone receptor relative to progesterone. Retroprogesterone is the parent compound of a group of progestins consisting of the marketed progestins dydrogesterone (6-dehydroretroprogesterone) and trengestone (1,6-didehydro-6-chlororetroprogesterone) and the never-marketed progestin Ro 6-3129, as well as the

active metabolite An active metabolite is an active form of a drug after it has been processed by the body. Metabolites of drugs An active metabolite results when a drug is metabolized by the body into a modified form which continues to produce effects in the body ...

s of these progestins like 20α-dihydrodydrogesterone and 20α-dihydrotrengestone (i.e., the 20α- hydroxylated analogues).

Chemistry

References

Abandoned drugs Diketones Pregnanes Progestogens {{Genito-urinary-drug-stub

Chemistry

See also

References