20α-Progerol;4-Pregnen-3-one-20α-ol;NSC 68630;Pregn-4-ene-20α-ol-3-one;Progesterol-20α;Δ4-Pregnene-20α-ol-3-one;20a-Hydroxypregn-4-en-3-one;Progesterone EP Impurity B (20(S)-Hydroxy Progesterone)
Δ4-Pregnen-20α-ol-3-one (Progesterone EP Impurity B) is the main metabolite of Progesterone (P755900). Studies shows regulation of estrogen receptor levels in breast cancer by Δ4-Pregnen-20α-ol-3-one and other progesterone metabolites.