Transport mechanisms of carnosine in SKPT cells: contribution of apical and basolateral membrane transporters
Laboratory studyOther animals
- Design
- Laboratory study
- Subjects
- Cell culture (SKPT cells, a rat kidney proximal tubule line); replicate numbers not stated in abstract
- Dose used in the study
- 10 micromolar tritiated carnosine for uptake studies, with concentration-dependence experiments at varying substrate levels
- Duration
- not stated in abstract (time-course uptake experiments)
- What was measured
- Uptake of tritiated carnosine across the apical and basolateral membranes of SKPT cells as a function of time, pH, inhibitors and concentration; transepithelial transport; influx, efflux and transepithelial clearances from a cellular compartment model; peptide transporter expression by RT-PCR.
What the authors reported
Carnosine uptake from the apical side was about 15-fold higher than from the basolateral side, and apical-to-basolateral transport was strongly limited by efflux across the basolateral membrane. Apical uptake had the high affinity, proton dependence, concentration dependence and inhibitor profile of PEPT2. The basolateral carrier was saturable and inhibited by PEPT2 substrates but non-concentrative, which the authors interpret as a facilitative transporter. They conclude that carnosine should accumulate substantially in kidney cells but be reabsorbed into blood only minimally, because of high apical influx via PEPT2 and very low basolateral efflux.
Limits of this study
In vitro work in a rat-derived cell line, not whole-animal or human data. Km values and the named inhibitors are not given in the abstract. PMID 18820998 belongs to this paper, not to the Pept2 null mouse study by Kamal et al.; that study is Kamal MA, Jiang H, Hu Y, Keep RF, Smith DE, Am J Physiol Regul Integr Comp Physiol 2009;296(4):R986-R991, PMID 19225147, and is filed separately as kamal-2009.yaml. Full text not read.
Source
PubMed 18820998 · doi:10.1007/s11095-008-9726-9
Entry checked against PubMed abstract (E-utilities) on 2026-10-19. The dose shown is the dose the researchers used. It is not a recommendation. How to read this page.