p-glycoprotein
Meaning of p-glycoprotein: P-glycoprotein is a transport protein present in many normal tissues that pumps drugs and toxins out of cells, sometimes contributing to drug resistance in cancer.
Definition of p-glycoprotein
P-glycoprotein is a protein found in the membrane of many normal cells throughout the body, including cells lining the intestine, liver, kidney, and the blood vessels that form the blood-brain barrier. Its main function is pumping certain drugs and other foreign substances out of cells, a protective mechanism that limits how much of these substances accumulate within tissue.
Because of this pumping action, p-glycoprotein influences how well certain oral medications are absorbed, how thoroughly some drugs are cleared from the body, and how readily particular drugs can cross into the brain. This makes it relevant to drug interactions, since one medication can sometimes affect how well p-glycoprotein handles another.
In cancer treatment, some tumor cells produce unusually high amounts of p-glycoprotein, which can pump anticancer drugs back out of the cell before they take effect, contributing to reduced effectiveness of certain chemotherapy drugs and a pattern known as multidrug resistance.
Also known as
Used in a sentence
The tumor's high p-glycoprotein expression was considered a possible factor in its reduced response to chemotherapy.
Good to know
P-glycoprotein is a normal transport protein relevant to ordinary drug absorption and interactions throughout the body, and its role in cancer drug resistance reflects the same underlying mechanism rather than a separate, cancer-specific protein.
Word origin
Where “p-glycoprotein” comes from
Formed from Greek glykys, meaning sweet, referring to the sugar groups attached to the protein, and protein, from Greek proteios, meaning primary or of first importance.