<unk> , or 16α-iodoestradiol, is a synthetic, steroidal, potent estrogen with slight preference for the ERα over the ERβ that is used in scientific research. The KD of<unk>  for the ERα is 0.6 nM and for the ERβ is 0.24 nM, a 4-fold difference in affinity, whereas estradiol is considered to have similar affinity for the two receptor subtypes. Unlike the case of the much weaker estriol (16α-hydroxyestradiol),<unk>  is considered to be equipotent with estradiol in terms of estrogenic activity. Radiolabeled 16α-125Iiodo-E2 has been employed in imaging to study the estrogen receptor.
16α-Iodo-E2
16α-LE2
11-Ketoprogesterone
17α-Hydroxypregnenolone
Methyl-1-testosterone
Estradiol palmitate
17α-Epiestriol
16α-Hydroxyestrone