Bile acid formation in primary human hepatocytes

AIM To evaluate a culture system for bile acidformation in primary human hepatocytes incomparison with HepG2 cells.METHODS Hepatocytes were isolated fromnormal human liver tissue and were cultured inserum-free William’s E medium.The medium wascollected and renewed every 24 h.Bile acids andtheir precursors in media were finally analysed bygas chromatography-mass spectrometry.RESULTS Cholic acid(CA)andchenodeoxycholic acid(CDCA)conjugated withglycine or taurine accounted for 70% and 25% oftotal steroids.A third of CDCA was alsoconjugated with sulphuric acid.Dexamethasoneand thyroid hormone alone or in combination didnot significantly effect bile acid formation.Theaddition of cyclosporin A(10 μmol/L)inhibited thesynthesis of CA and CDCA by about 13% and30%,respectively.CONCLUSION Isolated human hepatocytes inprimary culture behave as in the intact liver byconverting cholesterol to conjugated CA andCDCA.This is in contrast to cultured HepG2 cells,which release large amounts of bile acidprecursors and unconjugated bile acids into themedium.