Figure 2. Hepatic bilirubin elimination.
Unconjugated bilirubin enters hepatocytes through the organic anion transporter (OATP) and is conjugated with glucuronic acid (GA) by UDP-glucuronyltransferase UGT1A1 and excreted by multi-drug resistant protein (MRP2) to bile. Soluble bilirubin is secreted back into the blood by MRP3.