5α,6β-Dihydroxycholestanol-d7 is intended for use as an internal standard for the quantification of 5α,6β-dihydroxycholestanol by GC- or LC-MS. 5α,6β-Dihydroxycholestanol is an oxysterol metabolite of cholesterol formed from conversion of cholesterol epoxides by 5,6-epoxysterol hydrolase.1,2 It inhibits NMDA-mediated calcium influx in HEK293 cells expressing NR1/NR2B NMDA receptors in a concentration-dependent manner. It also binds to voltage-gated sodium (Nav) channels and decreases action potentials in hippocampal neurons in vitro when used at a concentration of 10 µM.2 It increases survival of spinal cord motoneurons, cortical neurons, and cerebellar granule neurons in vitro when used at concentrations ranging from 5 to 15 µM.3 5α,6β-Dihydroxycholestanol is neuroprotective in a rat model of cerebral ischemia when administered at a dose of 12 mg/kg and increases latency to seizure onset and reduces severity of seizures induced by pentylenetetrazole in rats. 5α,6β-Dihydroxycholestanol has been used as a replacement for cholesterol in the study of cholesterol binding proteins.4
1.Aringer, L., and Eneroth, P.Formation and metabolism in vitro of 5,6-epoxides of cholesterol and β-sitosterolJ. Lipid Res.15(4)389-398(1974) 2.Tang, L., Yan, M., Leng, T., et al.Cholestane-3β, 5α, 6β-triol suppresses neuronal hyperexcitability via binding to voltage-gated sodium channelsBiochem. Biophys. Res. Commun.496(1)95-100(2018) 3.Hu, H., Zhou, Y., Leng, T., et al.The major cholesterol metabolite cholestane-3β,5α,6β-triol functions as an endogenous neuroprotectantJ. Neurosci.34(34)11426-11438(2014) 4.Sheng, R., Kim, H., Lee, H., et al.Cholesterol selectively activates canonical Wnt signalling over non-canonical Wnt signallingNat. Commun.5:4393(2014)