Simultaneous determination of mevalonate and 7 alpha-hydroxycholesterol in human plasma by gas chromatography-mass spectrometry as indices of cholesterol and bile acid biosynthesis.
A very sensitive and specific method for the simultaneous determination of mevalonate and 7 alpha-hydroxycholesterol in human plasma is described. The assay is based on isotope dilution mass spectrometry: the extracts from plasma were treated with benzylamine followed by dimethylethylsilylimidazole, then the resulting dimethylethylsilyl ether derivatives of mevalonylbenzylamide and 7 alpha-hydroxycholesterol were determined by gas chromatography-mass spectrometry using high-resolution selected-ion monitoring. Simple regression analysis revealed significant correlations between the plasma level of mevalonate and the hepatic activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (EC 1.1.1.34) (r = 0.83, P < 0.01) and between the plasma level of free 7 alpha-hydroxycholesterol and the hepatic activity of cholesterol 7 alpha-hydroxylase (EC 1.14.13.7) (r = 0.76, P < 0.05).
Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
T
T
Yoshida
A
A
Honda
N
N
Tanaka
Y
Y
Matsuzaki
B
B
He
T
T
Osuga
N
N
Kobayashi
K
K
Ozawa
H
H
Miyazaki
D000328:Adult; D000368:Aged; D001189:Aryl Hydrocarbon Hydroxylases; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D002769:Cholelithiasis / Q000378:metabolism; D002784:Cholesterol / Q000096:biosynthesis*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D005770:Gastrointestinal Neoplasms / Q000378:metabolism; D006801:Humans; D006888:Hydroxycholesterols / Q000097:blood*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D008297:Male; D008798:Mevalonic Acid / Q000097:blood*; D008862:Microsomes, Liver / Q000378:metabolism; D008875:Middle Aged; D013250:Steroid Hydroxylases / Q000378:metabolism
D001647:Bile Acids and Salts; D006888:Hydroxycholesterols; C011724:cholest-5-en-3 beta,7 alpha-diol; D003577:Cytochrome P-450 Enzyme System; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C029009:steroid hormone 7-alpha-hydroxylase; D002790:Cholesterol 7-alpha-Hydroxylase; D008798:Mevalonic Acid