| The constitutive androstane receptor (CAR) also known as nuclear receptor subfamily 1, group I, member 3 is a protein that in humans is encoded by the NR1I3 gene. CAR is a member of the nuclear receptor superfamily and along with pregnane X receptor (PXR) functions as a sensor of endobiotic and xenobiotic substances. In response, expression of proteins responsible for the metabolism and excretion of these substances is upregulated. Hence, CAR and PXR play a major role in the detoxification of foreign substances such as drugs.
Androstenol and several isomers of androstanol, androstanes, are endogenous antagonists of the CAR, and despite acting as antagonists, were the basis for the naming of this receptor. More recently, dehydroepiandrosterone (DHEA), also an androstane, has been found to be an endogenous agonist of the CAR. |
