title: Functional characterization of apical transporters expressed in rat proximal tubular cells (PTCs) in primary culture.
abstract: Since in vitro cell culture models often show altered apical transporter expression, they are not necessarily suitable for the analysis of renal transport processes. Therefore, we aimed here to investigate the usefulness of primary-cultured rat proximal tubular cells (PTCs) for this purpose. After isolation of renal cortical cells from rat kidneys, PTCs were enriched and the gene expression and function of apical transporters were analyzed by means of microarray, RT-PCR and uptake experiments. RT-PCR confirmed that the major apical transporters were expressed in rat PTCs. Na(+)-dependent uptake of α-methyl-d-glucopyranoside (αMG), ergothioneine and carnitine by the PTCs suggests functional expression of Sglts, Octn1 and Octn2, respectively. Inhibition of pH-dependent glycylsarcosine uptake by low concentration of cephalexin, which is a β-lactam antibiotics recognized by Pepts, indicates a predominant role of high affinity type Pept2, but not low affinity type Pept1, in the PTCs. Moreover, the permeability ratio of [(14)C]αMG (apical to basolateral/basolateral to apical) across PTCs was 4.3, suggesting that Sglt-mediated reabsorptive transport is characterized. In conclusion, our results indicate that rat PTCs in primary culture are found to be a promising in vitro model to evaluate reabsorption processes mediated at least by Sglts, Pept2, Octn1 and Octn2.
authors: Department of Membrane Transport and Biopharmaceutics, Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 Japan.
authors: Takeo
authors: T
authors: Nakanishi
authors: Akimasa
authors: A
authors: Fukushi
authors: Masanobu
authors: M
authors: Sato
authors: Mayuko
authors: M
authors: Yoshifuji
authors: Tomoka
authors: T
authors: Gose
authors: Yoshiyuki
authors: Y
authors: Shirasaka
authors: Kazuyo
authors: K
authors: Ohe
authors: Masato
authors: M
authors: Kobayashi
authors: Keiichi
authors: K
authors: Kawai
authors: Ikumi
authors: I
authors: Tamai
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats
chemical_list: D026901:Membrane Transport Proteins; D012333:RNA, Messenger