equilin

Equilin is a naturally occurring estrogenic steroid hormone found in horses and used as a medication. It is one of the principal estrogens present in conjugated estrogen preparations such as Premarin and esterified estrogens. Equilin acts primarily as an estrogen receptor agonist but has lower affinity for the receptor compared to estradiol. It promotes growth and development of female reproductive tissues and secondary sex characteristics. In vitro studies show that equilin inhibits 17β-hydroxysteroid dehydrogenase type 1, which catalyzes the conversion of estrone to estradiol. Equilin also displays endothelium-independent vasodilator effects by blocking L-type calcium channels on vascular smooth muscle cells. Additionally, it has been shown to promote cortical neuron growth via an NMDA receptor-dependent mechanism. Equilin is a major component (20–30%) of conjugated equine estrogens used for hormone replacement therapy in postmenopausal women.

Other names

1,3,5,7-estratetraen-3-ol-17-one7-dehydroestronedihydroequilenin3-hydroxyestra-1,3,5(10),7-tetraen-17-one