Incubation of 3α, 7α-dihydroxy-5β-cholestan-26-oic acid and its Δ24- analog with rat liver homogenate produced a mixture of C-24, 25 diastereoisomers of 3α, 7α, 24-trihydroxy-5β-cholestan-26-oic acid, a key intermediate of chenodeoxycholic acid biosynthesis.