These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Characterization of fluorescein transport in isolated proximal tubular cells of the rat: evidence for mitochondrial accumulation.
    Author: Masereeuw R, van den Bergh EJ, Bindels RJ, Russel FG.
    Journal: J Pharmacol Exp Ther; 1994 Jun; 269(3):1261-7. PubMed ID: 8014869.
    Abstract:
    The uptake and accumulation of the organic anion fluorescein-sodium (Flu-Na) was investigated in freshly isolated proximal tubular cells (PTC) of the rat kidney. Furthermore, the influence of other organic anions on Flu-Na uptake was studied in order to characterize Flu-Na transport in PTC. Flu-Na showed concentration-dependent, saturable and probenecid-sensitive transport. Comparing the transport parameters with para-aminohippurate (PAH), Flu-Na exhibited a higher affinity, but lower capacity to the organic anion transport system. The apparent Km for Flu-Na transport was 59 +/- 15 microM with a Vmax of 186 +/- 26 pmol/mg of protein/min, and for PAH 207 +/- 11 microM and 740 +/- 46 pmol/mg of protein/min, respectively. Dose-dependent inhibition of Flu-Na uptake with PAH resulted in an apparent inhibition constant Ki of 249 microM. This is in good agreement with the apparent Km of PAH, indicating that Flu-Na uptake is regulated by the PAH transport system. It is suggested that cellular uptake of both organic anions is mediated by a carrier at the basolateral membrane. However, after incubating cells with different concentrations of phenol red the percentage of maximum inhibition was 84%, which was significantly different from the 32% with PAH, suggesting that another transport system may be involved in Flu-Na uptake. Experiments with confocal laser scanning microscopy showed cellular uptake of Flu-Na and accumulation in subcellular structures. After superfusion of PTC with rhodamine 123 these structures were identified as mitochondria.
    [Abstract] [Full Text] [Related] [New Search]