Intestinal uptake transporters for metformin

Intestinal uptake transporters for metformin are a collective group of solute carrier (SLC) proteins that facilitate the absorption of the biguanide drug metformin from the intestinal lumen into enterocytes. Because metformin is highly hydrophilic and carries a positive charge at physiological pH, it cannot cross biological membranes by passive diffusion and relies entirely on carrier-mediated transport. The primary apical transporters involved in this process include the plasma membrane monoamine transporter (PMAT; SLC29A4), organic cation transporter 3 (OCT3; SLC22A3), and thiamine transporter 2 (THTR2; SLC19A3), with minor contributions from the serotonin transporter (SERT; SLC6A4) and choline high-affinity transporter (CHT; SLC5A7). Organic cation transporter 1 (OCT1; SLC22A1) also contributes to intestinal disposition, although its exact membrane localization in humans remains a subject of investigation. These transporters are critical determinants of metformin's oral bioavailability and are frequently implicated in the drug's common gastrointestinal side effects, such as nausea and diarrhea, which occur when high local concentrations of metformin accumulate in the gut. Genetic polymorphisms in these transporter genes, particularly SLC22A1 and SLC22A3, are associated with significant inter-individual variability in clinical response and drug tolerance.

Other names

Metformin intestinal transportersApical organic cation transportersIntestinal metformin uptake systemSLC29A4SLC22A3SLC22A1SLC19A3SLC6A4SLC5A7

Facilitated diffusion and active transport of organic cations across the apical membrane of intestinal epithelial cells.