Figure 2.

Schematic representation of the biochemical mechanisms in drug-induced cholestasis. Primary bile acids cholic and chenodeoxycholic acid are synthesized by hepatocytes, conjugated with taurine, glycine, and sulphate, and excreted into bile, reaching the intestine. There, the bacterial flora modifies them, de-conjugating and oxidizing to deoxycholic and lithocholic acid which is reabsorbed into blood, uptake by hepatocytes and conjugated again. There are ca. 40 different bile acid species in humans that can be properly analysed by metabolomics [49] and help to discriminate among the different causes of cholestasis.