Summary
When MDCK cells are cultured in MEM, they maintain a high concentration of three amino acids: glutamate (25mm), taurine (19 mm) and glycine (9 mm). With incubation of the cells in hypotonic media, the contents of these amino acids measured by HPLC are reduced in different time courses: taurine decreases most rapidly, followed by glutamate and glycine. All these losses are Na+ independent. To determine the transport mechanism activated by the hypotonic media, increasing external concentrations reaching 60 mm for nine different amino acids in Na+-free media were tested separately. For the five neutral (zwitterionic) amino acids, taurine, glycine, alanine, phenylalanine and tryptophan, cell contents increased linearly with external concentrations in hypotonic media, whereas in isotonic media only a slight rise was observed. The two anionic amino acids, glutamate and aspartate, were also increased linearly with their external concentrations in hypotonic media, but the changes were lower than those found for neutral amino acids. The presence of a negative membrane potential was responsible for this behavior since, using a K+ hypotonic medium which clamps the potential to zero, the glutamate content was found to increase linearly with an amplitude similar to the one observed for neutral amino acid. When external concentrations of two cationic amino acids, arginine and lysine, were increased in hypotonic media, only a small change, similar to that in isotonic media, was observed. These results indicate that a diffusion process for neutral and anionic amino acids is activated by a volume increase and it is suggested that an anion channel is involved.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Banderali, U., Roy, G. 1991. Ionic conductances activated during volume regulation in MDCK cells: a patch clamp study. Biophys. J. 59, 254a
Banderali, U., Roy, G. 1992. Activation of K+ and Cl− channels in MDCK cells during volume regulation in hypotonic media. J. Membrane Biol. 126:219–234
Boerner, P., Evans-Layng, M., Sang, H., Saier, M.H. Jr. 1986. Polarity of neutral amino acid transport and characterization of a broad specificity transport activity in a kidney epithelial cell line, MDCK. J. Biol. Chem. 261:13957–13962
Brunner, J., Graham, D.E., Hauser, H., Semenza, G. 1980. Ion and sugar permeabilities of lecithin bilayers: comparison of curved and planar bilayers. J. Membrane Biol. 57:133–141
Chamberlain, M.E., Strange, K. 1989. Anisosmotic cell volume regulation: a comparative review. Am. J. Physiol. 257:C159-C173
Garcia-Perez, A., Burg, M.B. 1991. Role of organic osmolytes in adaptation of renal cells to high osmolality. J. Membrane Biol. 119:1–13.
Gilles, R. 1979. Intercellular organic osmotic effectors. In: Mechanism of Osmoregulation in Animals: Maintenance of Cell Volume. R. Gilles, editor. pp. 111–154. New York, John Wiley & Sons.
Haussinger, D., Lang, F. 1989. Exposure of perfused liver to hypotonic conditions modifies cellular nitrogen metabolism. J. Cell. Biochem. 43:355–361
Hoffmann, E.K., Lambert, I.H. 1983. Amino acid transport and cell volume regulation in Ehrlich ascites tumor cells. J. Physiol. 338:613–625
Jones, D.P., Miller, L.A., Russell, W.C. 1990. Adaptive regulation of taurine transport in two continuous renal epithelial cell lines. Kidney Int. 38:219–226
Jones, B.N., Gilligan, J.P. 1983. o-Phthaldialdehyde precolumn derivatization and reverse-phase high performance liquid chromatography of polypeptide hydrolysates and physiological fluids. J. Chromatogr. 266:471–482
Roy, G., Sauvé, R. 1987. Effect of anisotonic media on volume, ion and amino-acid content and membrane potential of kidney cells (MDCK) in culture. J. Membrane Biol. 100:83–96
Sanchez-Olea, R., Moran, J. Shousboe, A., PasantesMorales, H. 1991. Hyposmolarity-activated fluxes of taurine in astrocytes are mediated by diffusion. Neurosci. Lett. 130:233–236
Sanchez-Olea, R., Pasantes-Morales, H., Lazaro, A., Cereijido, M. 1991. Osmolarity-sensitive release of free amino acids from cultured kidney cells (MDCK). J. Membrane Biol. 121:1–9
Semenza, G., Corcelli, A. 1986. The absorption of sugars and amino acids across the small intestine. In: Molecular and Cellular Basis of Digestion. P. Denuelle, editor. pp. 381–412. Amsterdam, Elsevier
Siebenz, A.W., Spring, K.R. 1989. A novel sorbitol transport mechanism in cultured renal papillary epithelial cells. Am. J. Physiol. 257:F937-F946
Stevens, B.R., Kaunitz, J.D., Wright, E.M. 1984. Intestinal transport of amino acids and sugars: Advances using membrane vesicles. Annu. Rev. Physiol. 46:417–433
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Roy, G., Malo, C. Activation of amino acid diffusion by a volume increase in cultured kidney (MDCK) cells. J. Membarin Biol. 130, 83–90 (1992). https://doi.org/10.1007/BF00233740
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00233740