1: J Lipid Res. 2007 Jun;48(6):1362-70. Epub 2007 Mar 1.

Ontogenic development-associated changes in the expression of genes involved in
rat bile acid homeostasis.

Cuesta de Juan S, Monte MJ, Macias RI, Wauthier V, Calderon PB, Marin JJ.

Laboratory of Experimental Hepatology and Drug Targeting, Centro de Investigación
Biomédica en Red for Hepatology and Gastroenterology Research (CIBERehd),
University of Salamanca, Salamanca, Spain.

Ontogenic changes in the rat bile acid (BA) pool, measured enzymatically and by
GC-MS, and expression of enzymes (5alpha-reductase, 5beta-reductase, and
cytochrome P450 enzymes Cyp7a1, Cyp8b1, Cyp27 and Cyp3a11), transporters [bile
salt export pump, sodium taurocholate-cotransporting polypeptide, apical
sodium-dependent bile acid transporter, and organic solute transporter alpha/beta
(Ostalpha/Ostbeta)], and nuclear receptors [fetoprotein transcription factor
(Ftf), farnesoid X receptor (Fxr), small heterodimer partner (Shp), and hepatic
nuclear factor 4alpha (HNF-4alpha)], determined by quantitative PCR, were
investigated. The absolute size of the BA pool increased progressively up to
adulthood, whereas the complexity of its composition was high in fetuses,
decreased after birth, increased again progressively up to adulthood, and
decreased in aged animals. Allo-cholic acid only appeared early in development,
in spite of low 5alpha-reductase expression. The relative size of the BA pool,
corrected by liver weight, was maintained from 1 week after birth, except at
weaning, when a transient peak accompanied by Shp downregulation and Cyp7a1
upregulation was observed. An imposed weaning delay of 1 week had no effect on
the time course of the BA pool size but decreased the proportion of
chenodeoxycholic and alpha-muricholic acids, whereas the proportion of cholic
acid was increased, probably as a result of Cyp8b1 upregulation. In conclusion,
changes in the expression of genes involved in BA homeostasis may play a role in 
physiological adaptations to digestive functions during the rat life span.

PMID: 17332599 [PubMed - indexed for MEDLINE]

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