Na(+)-dependent, active nucleoside transport in mouse spleen lymphocytes, leukemia cells, fibroblasts and macrophages, but not in equivalent human or pig cells; dipyridamole enhances nucleoside salvage by cells with both active and facilitated transport.

Abstract

Formycin B influx studies have shown that P388 and L1210 mouse leukemia cells, mouse L929 cells, mouse RAW 309 Cr.1 cells, LK35.2 mouse B-cell hybridoma cells and cultured mouse peritoneal macrophages express both Na(+)-dependent, active and nonconcentrative, facilitated nucleoside transport systems. In the mouse cell lines, active transport represented only a minor nucleoside transport component and was detected only by measuring formycin B uptake in the presence of dipyridamole or nitrobenzylthioinosine, strong inhibitors of facilitated, but not of active, nucleoside transport. Inhibition of facilitated transport resulted in the concentrative accumulation of formycin B in cells expressing active nucleoside transport. Concentrative formycin B accumulation was abolished by treatment of the cells with gramicidin or absence of Na+ in the extracellular medium and strongly inhibited by ATP depletion or ouabain treatment. Mouse macrophages accumulated formycin B to 70-times the extracellular concentration in the absence of dipyridamole during 90 min of incubation at 37 degrees C. Thus active transport represents a major nucleoside transport system of these cells, similarly as previously reported for mouse spleen lymphocytes. In contrast to the various types of mouse cells, active formycin B transport was not detected in human HeLa cells, human H9, Jurkat and CEM T lymphoidal cells and pig spleen lymphocytes. These cells expressed only facilitated nucleoside transport with kinetic properties similar to those of the facilitated transporters of other mammalian cells.

• Authors: P G Plagemann, J M Aran
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1025 Issue 1 Pg. 32-42 (Jun 11 1990) ISSN: 0006-3002 [Print] Netherlands
• PMID: 2369575 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Formycins
• Nucleosides
• formycin B
• Dipyridamole
• Sodium
• Phlorhizin

Topics

• Animals
• Biological Transport, Active
• Cells, Cultured
• Dipyridamole (pharmacology)
• Fibroblasts (metabolism)
• Formycins (metabolism)
• Humans
• Kinetics
• Leukemia L1210 (metabolism)
• Leukemia P388 (metabolism)
• Lymphocytes (metabolism)
• Macrophages (metabolism)
• Nucleosides (metabolism)
• Phlorhizin (pharmacology)
• Sodium (pharmacology)
• Spleen (drug effects, metabolism, pathology)
• Swine
• Tumor Cells, Cultured