Genetically modified mouse models for oral drug absorption and disposition

Area of Science:

• Pharmacology and Drug Metabolism
• Gastrointestinal Physiology
• Molecular Biology

Background:

• Oral drug administration relies heavily on intestinal absorption.
• Enterocyte transmembrane transporters play a crucial role in mediating drug uptake and efflux.
• Understanding these transporters is key to optimizing oral drug bioavailability and efficacy.

Purpose of the Study:

• To investigate the role of various drug transporters in intestinal drug absorption.
• To analyze data from knockout mouse models to elucidate transporter functions in vivo.
• To identify specific transporters that limit or facilitate the absorption of orally administered drugs.

Main Methods:

• Review and analysis of studies utilizing knockout mouse models for drug transporters.
• Examination of in vivo and in vitro data related to drug transport across the intestinal epithelium.
• Focus on transporters such as Mrp2, Octn1, Octn2, Ent1, Mrp3, Mrp4, Oct1, Oct2, and Oatp.

Main Results:

• Multidrug resistance-associated protein 2 (Mrp2) was found to limit intestinal drug absorption.
• Equilibrative nucleoside transporter 1 (Ent1), Mrp3, and potentially Mrp4 facilitate intestinal drug uptake.
• Organic cation transporter n1 (Octn1) and Octn2 may facilitate absorption, but direct in vivo evidence is limited; Oct1, Oct2, Oatp 1a, and 1b showed no significant role.

Conclusions:

• Specific drug transporters differentially regulate intestinal drug absorption.
• Mrp2 acts as a barrier, while Ent1, Mrp3, and Mrp4 promote drug absorption.
• Further research is needed to confirm the in vivo roles of Octn1 and Octn2 in intestinal drug absorption.