Differences in hepatic levels of intermediates in bile acid biosynthesis between Cyp27(-/-) mice and CTX.

Article Details

Citation

Copy to clipboard

Honda A, Salen G, Matsuzaki Y, Batta AK, Xu G, Leitersdorf E, Tint GS, Erickson SK, Tanaka N, Shefer S

Differences in hepatic levels of intermediates in bile acid biosynthesis between Cyp27(-/-) mice and CTX.

J Lipid Res. 2001 Feb;42(2):291-300.

PubMed ID

11181760 [ View in PubMed

]

Abstract

Cerebrotendinous xanthomatosis (CTX) is a rare, recessively inherited lipid storage disease characterized by a markedly reduced production of chenodeoxycholic acid and an increased formation of 25-hydroxylated bile alcohols and cholestanol. Patients with this disease are known to have mutations in the sterol 27-hydroxylase (Cyp27) gene. However, one study showed that mice with a disrupted Cyp27 gene did not have any CTX-related clinical or biochemical abnormalities. To explore the reason, hepatic cholesterol, cholestanol, and 12 intermediates in bile acid biosynthetic pathways were quantified in 10 Cyp27(-/-) and 7 Cyp27(+/+) mice, two CTX patients (untreated and treated with chenodeoxycholic acid), and four human control subjects by high resolution gas chromatography-mass spectrometry. Mitochondrial 27-hydroxycholesterol and 5beta-cholestane-3alpha,7alpha,12alpha,27-tetrol were virtually absent in both Cyp27(-/-) mice and CTX patients. In Cyp27(-/-) mice, microsomal concentrations of intermediates in the early bile acid biosynthetic pathway (7alpha-hydroxycholesterol, 7alpha-hydroxy-4-cholesten-3-one, 7alpha,12alpha-dihydroxy-4-cholesten-3-one, and 5beta-cholestane-3alpha,7alpha,12alpha-triol), 25-hydroxylated bile alcohols (5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol, 5beta-cholestane-3alpha,7alpha,12alpha,23R,25-pentol, and 5beta-cholestane-3alpha,7alpha,12alpha,24R, 25-pentol), and cholestanol were all significantly elevated compared with those in Cyp27(+/+) mice, although the levels were lower than those in untreated CTX patients. The intermediate levels in early bile acid biosynthesis were more elevated in male (16;-86% of CTX) than in female Cyp27(-/-) mice (7-30% of CTX). In contrast, 25-hydroxylated bile alcohol concentrations were not significantly different between male and female Cyp27(-/-) mice and were considerably lower (less than 14%) than those in CTX patients.These results suggest that 1) in Cyp27(-/-) mice, especially in females, classic bile acid biosynthesis via 7alpha-hydroxycholesterol is not stimulated as much as in CTX patients; and 2) formed 25-hydroxylated bile alcohols are more efficiently metabolized in Cyp27(-/-) mice than in CTX patients.

DrugBank Data that Cites this Article

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Chenodeoxycholic acid	Sterol 26-hydroxylase, mitochondrial	Protein	Humans	Unknown	Substrate	Details