Human NTCP (sodium taurocholate cotransporting polypeptide) is mainly expressed at the basolateral (sinusoidal) membrane of hepatocytes and is essentially involved in the enterohepatic circulation of bile acids mediating the first step in the cellular uptake of bile acids through the membrane barriers in the liver. Here, it mediates sodium-coupled uptake of taurocholate and other bile acids with a Na+:taurocholate stoichiometry of 2:1. NTCP also transports steroid sulfates like estrone-3-sulfate and DHEAS. Furthermore, NTCP is a cell surface receptor necessary for the entry of hepatitis B and hepatitis D virus.
Inhibition of hNTCP mediated Estrone-3-sulfate uptake by different drugs (100 µM)