8,9-Dehydroestradiol

8,9-Dehydroestradiol, or Δ⁸-17β-estradiol, also known as estra-1,3,5(10),8-tetraen-17β-ol-3-one, is a naturally occurring steroidal estrogen found in horses which is closely related to equilin, equilenin, and estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent of conjugated estrogens (Premarin).[1] It is also an important active metabolite of 8,9-dehydroestrone, analogously to conversion of estrone or estrone sulfate into estradiol.[2][3]

Composition of conjugated estrogens and properties of constituents

Compound	Synonym	Proportion (%)	Relative potency in the vagina (%)	Relative potency in the uterus (%)	RBA for ERα (%)	RBA for ERβ (%)	ERα / ERβ RBA ratio
Conjugated estrogens	–	100	38	100	–	–	–
Estrone	–	49.1–61.5	30	32	26	52	0.50
Equilin	Δ^7-Estrone	22.4–30.5	42	80	13	49	0.26
17α-Dihydroequilin	Δ^7-17α-Estradiol	13.5–19.5	0.06	2.6	41	32	1.30
17α-Estradiol	–	2.5–9.5	0.11	3.5	19	42	0.45
Δ^8-Estrone	–	3.5–3.9	?	?	19	32	0.60
Equilenin	Δ^6,8-Estrone	2.2–2.8	1.3	11.4	15	20–29	0.50–0.75
17β-Dihydroequilin	Δ^7-17β-Estradiol	0.5–4.0	83	200	113	108	1.05
17α-Dihydroequilenin	Δ^6,8-17α-Estradiol	1.2–1.6	0.018	1.3	20	49	0.40
17β-Estradiol	–	0.56–0.9	100	?	100	100	1.00
17β-Dihydroequilenin	Δ^6,8-17β-Estradiol	0.5–0.7	0.21	9.4	68	90	0.75
Δ^8-17β-Estradiol	–	Small amounts	?	?	68	72	0.94
Notes: All listed compounds are present in conjugated estrogen products specifically in the form of the sodium salts of the sulfate esters (i.e., as sodium estrone sulfate, sodium equilin sulfate, etc.). Sources: See template.

8,9-Dehydroestradiol

Clinical data
Other names	Δ^8-Estradiol; Δ^8-17β-Estradiol; Estra-1,3,5(10),8-tetraen-17β-ol-3-one
Routes of administration	By mouth
Drug class	Estrogen
Identifiers
IUPAC name (13S,14S,17S)-13-methyl-6,7,11,12,14,15,16,17-octahydrocyclopenta[a]phenanthrene-3,17-diol
CAS Number	23392-54-3
ChemSpider	8014038
Chemical and physical data
Formula	C18H22O2
Molar mass	270.372 g·mol^−1
3D model (JSmol)	Interactive image
SMILES Oc4cc3c(/C1=C(/[C@@H]2CC[C@H](O)[C@]2(CC1)C)CC3)cc4
InChI InChI=InChI=1S/C18H22O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h3,5,10,16-17,19-20H,2,4,6-9H2,1H3/t16-,17-,18-/m0/s1 Key:UWYDUSMQFLTKBQ-BZSNNMDCSA-N

See also

• List of estrogens § Equine estrogens

References

1. Marc A. Fritz; Leon Speroff (28 March 2012). Clinical Gynecologic Endocrinology and Infertility. Lippincott Williams & Wilkins. pp. 751–. ISBN 978-1-4511-4847-3.
2. Kuhl H (2005). "Pharmacology of estrogens and progestogens: influence of different routes of administration". Climacteric. 8 Suppl 1: 3–63. doi:10.1080/13697130500148875. PMID 16112947.
3. Bhavnani BR, Nisker JA, Martin J, Aletebi F, Watson L, Milne JK (2000). "Comparison of pharmacokinetics of a conjugated equine estrogen preparation (premarin) and a synthetic mixture of estrogens (C.E.S.) in postmenopausal women". J. Soc. Gynecol. Investig. 7 (3): 175–83. doi:10.1016/s1071-5576(00)00049-6. PMID 10865186.