Combined Liquid Chromatography–Tandem Mass Spectrometry Analysis of Progesterone Metabolites
Fig 6
Progesterone metabolites formed in the HES cell line.
Histogram representing the percentages of progesterone and its most abundant metabolites detected at different times. The scheme of the proposed metabolism is shown below. The main pathway is marked in bold. First, the 20-keto group of progesterone is reduced to form (20S)-20-hydroxy-pregn-4-ene-3-one, which is reduced at position C5 to form (20S)-20-hydroxy-5α-pregnane-3-one. Then (20S)-20-hydroxy-5α-pregnane-3-one is further metabolized at the 3-keto group, to form mainly (20S)-5α-pregnane-3α,20-diol, and also (20S)-5α-pregnane-3β,20-diol to a lesser extent.