Endogenous Metabolite
Pregnane X receptor (PXR)

7α-Hydroxy-4-cholesten-3-one is found relatively upstream in the biosynthetic pathway to bile acids (e.g. chenodeoxycholic acid). The first step is the incorporation of the 7α-hydroxy group onto cholesterol by cytochrome P450 7A1, and the second step is the oxidation and isomerization of the 3-hydroxy group and the Δ5,6-double bond by 3β-hydroxy steroid dehydrogenase to yield 7α-Hydroxy-4-cholesten-3-one. The deletion of the gene that expresses P450 27A1, which is found downstream in the bile acid pathway, results in the accumulation of the precursor, 7α-Hydroxy-4-cholesten-3-one.

7α-Hydroxy-4-cholesten-3-one strongly relates to the hepatic enzymatic activity of CYP7A1 at steady-state conditions as well as during the rapid diurnal changes that occur in the rat. That serum 7α-Hydroxy-4-cholesten-3-one has a pronounced diurnal rhythm.