16α-LE2

16α-LE2, or 16α-lactone-estradiol, also known as 3,17β-dihydroxy-19-nor-17α-pregna-1,3,5-(10)-triene-21,16α-lactone, is a synthetic, steroidal estrogen featuring an estradiol core. It is a highly potent and selective agonist of the ERα that is used in scientific research to study the function of the ERα.[1][2] It has 265-fold higher potency in transactivation assays of the ERα relative to the ERβ and 70-fold preference in binding affinity for the ERα over the ERβ.[2]

16α-LE2

Identifiers
IUPAC name 3,17β-Dihydroxy-16α,21-epoxy-19-nor-17α-pregna-1,3,5(10)-trien-21-one
CAS Number	406483-39-4
ChemSpider	8037946
Chemical and physical data
Formula	C20H24O4
Molar mass	328.408 g·mol^−1
3D model (JSmol)	Interactive image
SMILES O=C1O[C@@]2([H])[C@]([C@@]3(C)CC[C@]4([H])C5=CC=C(C=C5CC[C@@]4([H])[C@]3([H])C2)O)(C1)O
InChI InChI=InChI=1S/C20H24O4/c1-19-7-6-14-13-5-3-12(21)8-11(13)2-4-15(14)16(19)9-17-20(19,23)10-18(22)24-17/h3,5,8,14-17,21,23H,2,4,6-7,9-10H2,1H3/t14-,15-,16+,17-,19+,20+/m1/s1 Key:NLUGVTJBNRSIKH-UQZPWQSVSA-N

In rodents, 16α-LE2 has no effect on ovarian follicle development, whereas the highly ERβ-selective agonist 8β-VE2 stimulates follicular growth and to a comparable extent as estradiol, indicating that the ERβ and not the ERα is involved in the effects of estrogen on ovarian follicles.[2][3] In contrast, 16α-LE2 stimulates uterine weight, whereas 8β-VE2 has no effect, indicating that the ERα and not the ERβ is involved in the effects of estrogen on the uterus.[2] Research has determined through experimental rodent studies with estradiol, 16α-LE2, and 8β-VE2 that the positive, protective effects of estrogens on bone formation resorption and bone mineral density are mediated via the ERα, whereas the ERβ does not appear to be involved.[4]

See also

• ERA-45
• ERA-63
• Propylpyrazoletriol
• Methylpiperidinopyrazole
• GTx-758
• Diarylpropionitrile
• WAY-200070
• 16α-Iodo-E2

References

1. I Shaw (31 March 2009). Endocrine-Disrupting Chemicals in Food. Elsevier. pp. 550–. ISBN 978-1-84569-574-3.
2. Hegele-Hartung C, Siebel P, Peters O, Kosemund D, Müller G, Hillisch A, Walter A, Kraetzschmar J, Fritzemeier KH (2004). "Impact of isotype-selective estrogen receptor agonists on ovarian function". Proc. Natl. Acad. Sci. U.S.A. 101 (14): 5129–34. doi:10.1073/pnas.0306720101. PMC 387385. PMID 15037755.
3. Tony M. Plant; Anthony J. Zeleznik (15 November 2014). Knobil and Neill's Physiology of Reproduction. Academic Press. pp. 1150–. ISBN 978-0-12-397769-4.
4. Hertrampf T, Schleipen B, Velders M, Laudenbach U, Fritzemeier KH, Diel P (2008). "Estrogen receptor subtype-specific effects on markers of bone homeostasis". Mol. Cell. Endocrinol. 291 (1–2): 104–8. doi:10.1016/j.mce.2008.03.003. PMID 18433985.