CYP3A4 and preeclampsia: To achieve these goals, we quantified 4β-OH-CHO, the 4β-OH-CHO:CHO ratio, and steroidal PRHs (E1, E2, P4, and CRT) in plasma obtained from healthy nonpregnant, healthy pregnant, and pregnant patients diagnosed with preeclampsia, and quantified the effects of PRHs on the absolute protein concentration of CYP3A4 (and other key CYP isoforms) in sandwich cultured human hepatocytes (SCHH).