The Brain Liver Intestine Na⁺ Channel (BLINaC) is a member of the DEG/ENaC family of ion channels, its function is completely unknown. In rodents, the blinac mRNA is expressed mainly in brain, liver, and intestine and to a lesser extent in lung and kidney. Despite a high degree of sequence identity (97%) BLINaCs from mouse and rat have profound electrophysiological differences. While BLINaC from rat (rBLINaC) is strongly inhibited by physiological concentrations of extracellular Ca²⁺ and consequently generates only small currents when expressed in Xenopus oocytes, BLINaC from mouse (mBLINaC) is a constitutively open Na⁺ channel. In order to explore the expression pattern of the BLINaC protein we generated a polyclonal antibody against a peptide representing the C-terminal domain of BLINaC and show that in the liver BLINaC prominently localizes to the apical region of rat and mouse cholangiocytes, epithelial cells lining the bile ducts. Furthermore, we show that rBLINaC is robustly activated by bile. We identified bile acids as the active molecules in bile, in particular hyodeoxycholic acid and chenodeoxycholic acid, suggesting that, in situ, rBLINaC is consitutively active, like mBLINaC. Taken together, our results suggest that BLINaC is an epithelial cation channel in bile ducts that is potentially involved in the modification of bile.