Interaction of Peptide Transporter 1 With D-Glucose and L-Glutamic Acid; Possible Involvement of Taste Receptors.

We investigated the influence of sweet and umami (savory) tastants on the intestinal absorption of cephalexin (CEX), a substrate of peptide transporter 1 (PEPT1, SLC15A1) in rats. After oral administration of glucose or mannitol to rats, CEX was administered together with a second dose of glucose or mannitol. Western blot analysis indicated that expression of PEPT1 in rat jejunum membrane was decreased by glucose, compared to mannitol.

Recommended Daily Dose of Sesame Lignans Has No Influence on Oral Absorption of P-Glycoprotein Substrates in Rats.

Sesamin (SM) and episesamin (ESM) are constituents of sesame seeds, which are used in health foods and considered to have various beneficial effects in the prevention of lifestyle-related diseases. P-Glycoprotein (P-gp) is an ATP-binding cassette transporter involved in drug absorption in the human gastrointestinal tract. A recent report indicated that SM influences P-gp-mediated drug transport.

Possible interaction of quinolone antibiotics with peptide transporter 1 in oral absorption of peptide-mimetic drugs.

The study investigated whether quinolone antibiotics inhibit the PEPT1-mediated uptake of its substrates. Among the quinolones examined, lomefloxacin, moxifloxacin (MFLX) and purlifloxacin significantly inhibited the uptake of PEPT1 substrate phenylalanine-Ψ(CN-S)-alanine (Phe-Ψ-Ala) in HeLa/PEPT1 cells to 31.6 ± 1.

Evaluation of a thiodipeptide, L-phenylalanyl-Ψ[CS-N]-L-alanine, as a novel probe for peptide transporter 1.

L-Phenylalanyl-Ψ[CS-N]-l-alanine (Phe-Ψ-Ala), a thiourea dipeptide, was evaluated as a probe for peptide transporter 1 (PEPT1). Uptake of Phe-Ψ-Ala in PEPT1-overexpressing HeLa cells was significantly higher than that in vector-transfected HeLa cells and the Km value was 275 ± 32 µM. The uptake was pH-dependent, being highest at pH 6.