3β-Dihydroprogesterone explained

3β-Dihydroprogesterone (3β-DHP), also known as 3β-hydroxyprogesterone, or pregn-4-en-3β-ol-20-one (4-pregnenolone, δ⁴-pregnenolone), is an endogenous steroid.^[1] It is biosynthesized by 3β-hydroxysteroid dehydrogenase from progesterone. Unlike 3α-dihydroprogesterone (3α-DHP), 3β-DHP does not act as a positive allosteric modulator of the GABA_A receptor, which is in accordance with the fact that other 3β-hydroxylated progesterone metabolites such as isopregnanolone and epipregnanolone similarly do not act as potentiators of this receptor and instead inhibit it as well as reverse the effects of potentiators like allopregnanolone.^[2] 3β-DHP has been reported to possess about the same potency as progesterone in a bioassay of progestogenic activity, whereas 3α-DHP was not assessed.^{[3] [4]}

See also

• 5α-Dihydroprogesterone
• 5β-Dihydroprogesterone
• 3β-Androstanediol
• Pregnenolone
• Progesterone 3-acetyl enol ether
• Quingestrone

Notes and References

1. Kavaliers, Martin. Wiebe, John P.. Galea, Liisa A.M.. Liisa Galea.
2. Prince. R.J.. Simmonds. M.A.. Differential antagonism by epipregnanolone of alphaxalone and pregnanolone potentiation of [3H]flunitrazepam binding suggests more than one class of binding site for steroids at GABAA receptors. Neuropharmacology. 32. 1. 1993. 59–63. 0028-3908. 10.1016/0028-3908(93)90130-U. 8381526 . 25766028 .
3. Junkermann H, Runnebaum B, Lisboa BP . New progesterone metabolites in human myometrium . Steroids . 30 . 1 . 1–14 . July 1977 . 919010 . 10.1016/0039-128X(77)90131-3 . 28420255 . In the Clauberg bioassay the 3β-hydroxy-4-pregnen-20-one shows about the same potency as progesterone (34). In regard to the biological activity of the 3α epimer no data are available..
4. Pincus G, Miyake T, Merrill AP, Longo P . The bioassay of progesterone . Endocrinology . 61 . 5 . 528–33 . November 1957 . 13480263 . 10.1210/endo-61-5-528 . free .