Gas chromatographic-mass spectrometric analyses of cholesterol and its precursors in rat plasma as tert-butyldimethylsilyl derivatives.

BACKGROUND Cholesterol and its metabolic precursors occurring in metabolic pathways are important biochemical indicators in pathological conditions. METHODS A method for the simultaneous determination of cholesterol and its metabolic precursors, such as lanosterol and 7-dehydrocholesterol, in rat plasma is demonstrated. It involves their extraction after saponification, followed by conversion to tert-butyldimethylsilyl (TBDMS) derivatives for analysis by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode (GC-SIM-MS). RESULTS The characteristic fragment ions of [M-57], m/z 443, 483, and 441 permitted the accurate and selective detection of cholesterol and its precursors in rat plasma. The whole procedure of TBDMS derivatization, with subsequent GC-SIM-MS analysis, was linear (r>or=0.9994), reproducible (% relative standard deviation=2.2 to 7.5), and accurate (% relative error=-5.6 to 7.7), with detection limits of 0.02 to 0.07 ng/ml. Recoveries were measured to be ranged from 89.5 to 95.4%. CONCLUSION The present method was useful for the quantification of cholesterol and its precursors in rat plasma samples of 1 microl.

[1]  E. Börjesson,et al.  New method for determination of fecal sterols in urine using non-chlorinated solvents. , 1998, Journal of chromatography. B, Biomedical sciences and applications.

[2]  J. Treadway,et al.  Dual-action hypoglycemic and hypocholesterolemic agents that inhibit glycogen phosphorylase and lanosterol demethylase Published, JLR Papers in Press, December 16, 2004. DOI 10.1194/jlr.M400436-JLR200 , 2005, Journal of Lipid Research.

[3]  A. Zafra-Gómez,et al.  Gas chromatographic-mass spectrometric determination of brain levels of α-cholest-8-en-3β-ol (lathosterol) , 2007 .

[4]  R. Kelley.  Diagnosis of Smith-Lemli-Opitz syndrome by gas chromatography/mass spectrometry of 7-dehydrocholesterol in plasma, amniotic fluid and cultured skin fibroblasts. , 1995, Clinica chimica acta; international journal of clinical chemistry.

[5]  C. Cannon.  Cardiovascular disease and modifiable cardiometabolic risk factors. , 2007, Clinical cornerstone.

[6]  L. Larsson,et al.  Determination of ergosterol in organic dust by gas chromatography-mass spectrometry. , 1995, Journal of chromatography. B, Biomedical applications.

[7]  J. Dietschy,et al.  Thematic review series: Brain Lipids. Cholesterol metabolism in the central nervous system during early development and in the mature animal Published, JLR Papers in Press, May 16, 2004. DOI 10.1194/jlr.R400004-JLR200 , 2004, Journal of Lipid Research.

[8]  G. Bakris.  Current Perspectives on Hypertension and Metabolic Syndrome , 2007, Journal of Managed Care Pharmacy.

[9]  F. Chevy,et al.  Changes in serum sterols of rats treated with 7-dehydrocholesterol-delta 7-reductase inhibitors: comparison to levels in humans with Smith-Lemli-Opitz syndrome. , 1996, Journal of lipid research.

[10]  Claude Gosselin,et al.  Selected ion monitoring of tert-butyldimethylsilyl cholesterol ethers for determination of total cholesterol content in foods , 1992 .

[11]  R. Evershed.  Handbook of Derivatives for Chromatography , 1993 .

[12]  C. Maraschiello,et al.  Determination of cholesterol in fat and muscle of pig by HPLC and capillary gas chromatography with solvent venting injection , 1996 .

[13]  U. Diczfalusy,et al.  The oxysterols cholest-5-ene-3β,4α-diol, cholest-5-ene-3β,4β-diol and cholestane-3β,5α,6α-triol are formed during in vitro oxidation of low density lipoprotein, and are present in human atherosclerotic plaques , 1996 .