Characteristics of pemetrexed transport by renal basolateral organic anion transporter hOAT3
Related Experiment Video
Updated: May 7, 2026

Characterization of Membrane Transporters by Heterologous Expression in E. coli and Production of Membrane Vesicles
Published on: December 31, 2019
Tomohiko Kurata1, Takuya Iwamoto, Yuki Kawahara
1Department of Clinical Pharmacy and Biopharmaceutics, Mie University Graduate School of Medicine.
Purpose:
Pemetrexed transport by human organic anion transporters, hOAT1 (SLC22A6) and hOAT3 (SLC22A8), were characterized in comparison with methotrexate.
Methods:
Accumulation of pemetrexed and methotrexate in hOAT1- and hOAT3-expressing cells were evaluated. Pemetrexed and methotrexate were determined by HPLC. Kinetic parameters were calculated by Eadie-Hofstee plot.
Results:
When HEK-hOAT3 and -hOAT1 cells were incubated with 100 µM pemetrexed for 30 min, pemetrexed was accumulated at 14- and 1.7-fold greater than that in control cells, respectively. Pemetrexed and methotrexate transport by hOAT3 was saturated at high concentrations with apparent Km values 28.2 µM and 76.6 µM, respectively. In addition, intrinsic activity (Vmax/Km) of pemetrexed and methotrexate transport by hOAT3 was 4.82 and 0.42 µl/min/mg protein, respectively, suggesting 11-fold higher transport of pemetrexed than methotrexate by hOAT3. Furthermore, loxoprofen, ibuprofen, pravastatin, and cefazolin, transport substrates of hOAT3, inhibited pemetrexed transport by hOAT3 with IC50 values, 34.2, 27.9, 76.3 and 650 µM, respectively.
Conclusions:
Pemetrexed is a superior substrate to methotrexate for hOAT3. Loxoprofen, ibuprofen, and cefazolin could cause drug-drug interactions when attaining high blood concentrations.
Related Concept Videos
Carrier-Mediated Transport
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
Drug Elimination by Renal Route: Tubular Secretion
Renal Drug Excretion: Tubular Secretion
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters
ABC Transporters: Exporter

