Pharmacodynamics<unk>  is an estrogen, or an agonist of the estrogen receptors (ERs), the ERα and ERβ. In terms of relative binding affinity for the ERs,<unk>  has about 113% and 108% of that of estradiol for the ERα and ERβ, respectively.<unk>  has about 83% of the relative potency of CEEs in the vagina and 200% of the relative potency of CEEs in the uterus. Of the equine estrogens, it shows the highest estrogenic activity and greatest estrogenic potency. Like CEEs as a whole,<unk>  has disproportionate effects in certain tissues such as the liver and uterus. Equilin, the second major component of conjugated estrogens after estrone, is reversibly transformed into<unk>  analogously to the transformation of estrone into estradiol. However, whereas the balance of mutual interconversion of estrone and estradiol is largely shifted in the direction of estrone, it is nearly equal in the case of equilin and<unk> . As such, although<unk>  is only a minor constituent of CEEs, it is, along with estradiol, the most important estrogen relevant to the estrogenic activity of the medication. Pharmacokinetics<unk>  has about 30% of the relative binding affinity of testosterone for sex hormone-binding globulin (SHBG), relative to 50% for estradiol. The metabolic clearance rate of<unk>  is 1,250 L/day/m2, relative to 580 L/day/m2 for estradiol.
17β-Dihydroequilin
17α-Dihydroequilin
17β-Dihydroequilenin
17α-Dihydroequilenin
5α-Dihydroethisterone
17α-Epiestriol
8,9-Dehydroestradiol
Testosterone hexahydrobenzoate