Notes: 3β-hydroxy-5-Cholestenoic acid is an active metabolite of cholesterol formed when cholesterol is metabolized by the cytochrome P450 (CYP) isomer CYP27A1.{41086} 3β-hydroxy-5-Cholestenoic acid is a modulator of γ-secretase that decreases amyloid β (1-42) peptide (Aβ42; EC50 = 250 nM) and increases Aβ38 levels with no effect on total Aβ in CHO2B7 cells. It decreases endogenous murine Aβ42 production by 60 and 75% in mouse postnatal neuron-glia cultures at concentrations of 3 and 10 μM, respectively.