Mammalian P-glycoproteins are active drug efflux transporters located in the plasma membrane. In the early nineties, we generated knockouts of the three P-glycoprotein genes of mice, the
Piet Borst, Alfred H. Schinkel
Overview of ABCB1 functional expression throughout the body.
Blue lines indicate the location of ABCB1. Small arrows indicate the direction of ABCB1-mediated transport. Bold green arrows indicate net body excretion of ABCB1 substrates. ABCB1 in the BBB and blood-testis and placental fetal-maternal barrier protects brain, testis, and fetus, respectively, from accumulation of ABCB1 substrates. ABCB1 in small and large intestine reduces intestinal uptake (oral availability) and mediates direct intestinal excretion of substrates. ABCB1 in liver and kidney mediates hepatobiliary and renal excretion of substrates. ABCB1 expression in tumor cells can contribute to multidrug resistance.