title: Transient changes in the expression pattern of key enzymes for bile acid synthesis during rat liver regeneration.
abstract: Changes in the expression patterns of genes involved in bile acid (BA) synthesis were investigated during rat liver regeneration that follows two-thirds partial hepatectomy. BAs in bile were measured by GC-MS and the absolute and relative abundance of specific mRNAs in the liver by RT-real-time quantitative PCR. Cyclin E mRNA, used as an indicator of liver cell proliferation, peaked at day 1. The levels of mRNA of alpha-fetoprotein transcription factor (FTF) and small heterodimer partner (SHP) were first reduced (day 1) and then (days 2-3) increased, when those of farnesoid X receptor (FXR) were also transiently enhanced. The early (day 1) up-regulation of Cyp7a1, and Cyp8b1, together with the down-regulation of Cyp27, was consistent with an increased proportion of cholic acid versus chenodeoxycholic acid and a progressive recovery in total BAs secretion. The transient appearance of flat BAs (allo-BAs plus Delta4-unsaturated-BAs) during rat liver regeneration was probably due to the changes in the expression ratio of steroid 5alpha- versus 5beta-reductase. Both were first (day 1) down-regulated and then up-regulated (5alpha-reductase more than 5beta-reductase). In conclusion, changes in the expression patterns of nuclear receptors and enzymes involved in BA synthesis are consistent with the transient modifications that occur in BA pool during rat liver regeneration.
authors.affiliation: Department of Physiology and Pharmacology, Campus Miguel de Unamuno E.I.D. S-09, University of Salamanca, 37007 Salamanca, Spain.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Monte
authors.forename: Maria
authors.initials: M
authors.lastname: Fernandez-Tagarro
authors.forename: Jose J G
authors.initials: JJ
authors.lastname: Marin
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry* / Q000378:metabolism; D001647:Bile Acids and Salts / Q000096:biosynthesis* / Q000737:chemistry; D042944:Cholestenone 5 alpha-Reductase / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006498:Hepatectomy; D022781:Hepatocytes / Q000166:cytology / Q000201:enzymology*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D001647:Bile Acids and Salts; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D006899:Mixed Function Oxygenases; D042944:Cholestenone 5 alpha-Reductase