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] Related Links Changes in the expression of genes related to bile acid synthesis and transport by the rat liver during hepatocarcinogenesis. [Clin Sci (Lond). 2005] PMID:15853769 Transient changes in the expression pattern of key enzymes for bile acid synthesis during rat liver regeneration. [Biochim Biophys Acta. 2005] PMID:15904869 On the mechanism of bile acid inhibition of rat sterol 12alpha-hydroxylase gene (CYP8B1) transcription: roles of alpha-fetoprotein transcription factor and hepatocyte nuclear factor 4alpha. [Biochim Biophys Acta. 2002] PMID:12069850 Nuclear receptor-mediated repression of human cholesterol 7alpha-hydroxylase gene transcription by bile acids. [J Lipid Res. 2001] PMID:11518759 Disrupted coordinate regulation of farnesoid X receptor target genes in a patient with cerebrotendinous xanthomatosis. [J Lipid Res. 2005] PMID:15576845