Transport characteristics of L-citrulline in renal apical membrane of proximal tubular cells
| Autor: | Akimasa Fukushi, Ikumi Tamai, Masanobu Sato, Keisuke Mitsuoka, Toshimichi Nakamura, Yoshiyuki Shirasaka, Takeo Nakanishi |
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| Rok vydání: | 2009 |
| Předmět: |
Male
Amino Acid Transport Systems Pharmaceutical Science Biology Renal protein reabsorption Kidney Tubules Proximal chemistry.chemical_compound Citrulline medicine Animals Humans Pharmacology (medical) RNA Messenger RNA Small Interfering Rats Wistar Cells Cultured Pharmacology chemistry.chemical_classification Kidney Renal oligopeptide reabsorption Reabsorption Cell Membrane Sodium Cell Polarity Biological Transport Epithelial Cells General Medicine Apical membrane Rats Amino acid Kinetics Amino Acid Transport Systems Neutral medicine.anatomical_structure chemistry Biochemistry Renal physiology Biophysics Amino Acid Transport Systems Basic RNA Interference |
| Zdroj: | Biopharmaceutics & Drug Disposition. 30:126-137 |
| ISSN: | 1099-081X 0142-2782 |
| DOI: | 10.1002/bdd.653 |
| Popis: | L-Citrulline has diagnostic potential for renal function, because its plasma concentration increases with the progression of renal failure. Although L-citrulline extracted by glomerular filtration in kidney is mostly reabsorbed, the mechanism involved is not clearly understood. The present study was designed to characterize L-citrulline transport across the apical membranes of renal epithelial tubular cells, using primary-cultured rat renal proximal tubular cells, as well as the human kidney proximal tubular cell line HK-2. L-Citrulline was transported in a Na+-dependent manner from the apical side of both cell types cultured on permeable supports with a microporous membrane. Kinetic analysis indicated that the transport involves two distinct Na+-dependent saturable systems and one Na+-independent saturable system in HK-2 cells. The uptake was competitively inhibited by neutral and cationic, but not anionic amino acids. Relatively large cationic and anionic compounds inhibited the uptake, but smaller ones did not. In HK-2 cells, mRNA expression of SLC6A19 and SLC7A9, which encode B0AT1 and b0,+AT, respectively, was detected by RT-PCR. In addition, L-citrulline transport was significantly decreased in HK-2 cells in which either SLC6A19 or SLC7A9 was silenced. Hence, these results suggest that amino acid transporters B0AT1 and b0,+AT are involved in the reabsorption of L-citrulline in the kidney, at least in part, by mediating the apical membrane transport of L-citrulline in renal tubule cells. Copyright © 2009 John Wiley & Sons, Ltd. |
| Databáze: | OpenAIRE |
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