Rapid Increase of Gastrointestinal P-Glycoprotein Functional Activity in Response to Etoposide Stimulation

Does P-glycoprotein predict response to chemotherapy?

Why some cancers are curable by chemotherapy while most are not is an enigma and a major challenge for cancer researchers. The use of anticancer drugs in appropriate dosages and combinations has improved response rates and prolonged life. Yet, it is not uncommon for a patient to have a relapse during a course of chemotherapy that was initially successful. The discovery more than a decade ago th...

Effect of Honey on CYP3A4 Enzyme and P-Glycoprotein Activity in Healthy Human Volunteers

The activity of cytochrome p450 isozyme 3A4 (CYP3A4) enzyme and P-glycoprotein (P-gp) is modulated by grapefruit juice and herbal drugs. CYP3A4 is the major phase I drug metabolizing enzyme and P-gp is an ATP-dependent drug efflux pump that regulates the intestinal absorption of orally administered drugs. Honey is commonly consumed as a dietary supplement. However, its influence on human CY...

evaluation of the functional role of p-glycoprotein in brain uptake of tramadol in rat

P-glycoprotein (P-gp/Abcb1), Abcc2, and Abcc3 determine the pharmacokinetics of etoposide.

PURPOSE Despite the extensive use of etoposide for the treatment of different malignant neoplasms, its main pharmacokinetic determinants are not completely defined. We aimed to study the impact of P-glycoprotein (P-gp/ABCB1) and the multidrug resistance proteins ABCC2 (MRP2) and ABCC3 (MRP3) on the pharmacokinetics of etoposide. EXPERIMENTAL DESIGN Abcb1a/1b(-/-), Abcc2(-/-), Abcc3(-/-), Abcb...

Sensitive and rapid bioassay for analysis of P-glycoprotein-inhibiting activity of chemosensitizers in patient serum.

Clinical studies of agents capable of reversing P-glycoprotein (Pgp)-mediated multidrug resistance have attracted much attention in recent years. One question of interest in such studies is whether the concentrations achieved by chemosensitizers are sufficient to inhibit Pgp function. The goal of the present study was to develop a reliable ex vivo bioassay for analysis of the Pgp-inhibiting act...