AJP - Renal Physiology, Vol 243, Issue 4 408-F415, Copyright © 1982 by American Physiological Society

ARTICLES

Cell volume regulation in the proximal convoluted tubule

J. Gagnon, D. Ouimet, H. Nguyen, R. Laprade, C. Le Grimellec, S. Carriere and J. Cardinal

To evaluate the effect of hyper- and hypotonicity on proximal convoluted tubule (PCT) cell volume, nonperfused PCT were studied in vitro with hypertonic solutions containing sodium chloride, urea, or mannitol (450 mosmol/kg H2O) and with hypotonic low sodium chloride solutions (160 mosmol/kg H2O). When the tubules were subjected to hypertonic peritubular solutions containing NaCl, cell volume immediately decreased by 15.5% and remained constant throughout the experimental period (60 min). With mannitol, the initial decrease was identical to that with NaCl (17.7%), but the PCT volume increased slightly during the experimental period. With urea, the decrease in cell volume was smaller (7%) and transient. In hypotonicity, the PCT swelled rapidly, but this swelling was followed by a rapid regulatory phase in which PCT volume nearly returned to control values after less than 10 min. With a potassium-free peritubular medium or 10(-3) M ouabain, the regulatory phase of hypotonicity completely disappeared, whereas the cells did not maintain their reduced volume in NaCl-induced hypertonicity. These results suggest that Na-K-ATPase plays an important role in the maintenance of a reduced cellular volume in hypertonicity and in the regulatory phase of hypotonicity, probably by an active extrusion of sodium and water from the cell.

This article has been cited by other articles:

				Y. Miyata, Y. Asano, and S. Muto Hyperosmotic urea activates basolateral NHE in proximal tubule from P-gp null and wild-type mice Am J Physiol Renal Physiol, October 1, 2002; 283(4): F771 - F783. [Abstract] [Full Text] [PDF]

				Y. Miyata, Y. Asano, and S. Muto Effects of P-glycoprotein on cell volume regulation in mouse proximal tubule Am J Physiol Renal Physiol, May 1, 2001; 280(5): F829 - F837. [Abstract] [Full Text] [PDF]

				W. C. O'Neill Physiological significance of volume-regulatory transporters Am J Physiol Cell Physiol, May 1, 1999; 276(5): C995 - C1011. [Abstract] [Full Text] [PDF]

				F. LANG, G. L. BUSCH, M. RITTER, H. VOLKL, S. WALDEGGER, E. GULBINS, and D. HAUSSINGER Functional Significance of Cell Volume Regulatory Mechanisms Physiol Rev, January 1, 1998; 78(1): 247 - 306. [Abstract] [Full Text] [PDF]

				Y. Miyata, K. Okada, S. Ishibashi, Y. Asano, and S. Muto P-gp-induced modulation of regulatory volume increase occurs via PKC in mouse proximal tubule Am J Physiol Renal Physiol, January 1, 2002; 282(1): F65 - F76. [Abstract] [Full Text] [PDF]

				Y. Miyata, Y. Asano, and S. Muto Hyperosmotic mannitol activates basolateral NHE in proximal tubule from P-glycoprotein null mice Am J Physiol Renal Physiol, April 1, 2002; 282(4): F718 - F729. [Abstract] [Full Text] [PDF]