P-Glycoprotein-A Unique Transporter Pump

P-Glycoprotein (P-gp)/MDR1 is the 170-kDa ABC drug transporter protein. It is a member of the ABC(ATP Binding Cassette)super family. It is involved in limiting the harmful exposure of toxins, drugs, and xenobiotics to the body by extruding them into the gastrointestinal tract, bile and urine. Drugs or substrates can cross into the cell membrane by simple diffusion, filtration, or by specialized transport. The first step in drug efflux is drug recognition by P-gp followed by ATP-binding and subsequent hydrolysis. Finally, the generated energy is utilized to efflux substrate outside the cell membrane through central pore. P-gp acts as a rate limiting step during various stages of pharmacokinetic of drug but mainly on the absorption. Different drugs have different impact on P-gp expression. Some drugs are substrate of p-gp while some are inducers or inhibitors of P-gp. Altered P-gp/MDR1 activity due to induction and/or inhibition can cause drug–drug interactions with altered drug pharmacokinetics and response of drug. P-gpmayshow gender basis differences and so drug effect in individuals.