Rat hepatocytes transport water mainly via a non-channel-mediated pathway

Motoyoshi Yano, Raul A. Marinelli, Stuart K. Roberts, Vijayan Balan, Linh Pham, James E. Tarara, Piet C. De Groen, Nicholas F La Russo

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

During bile formation by the liver, large volumes of water are transported across two epithelial barriers consisting of hepatocytes and cholangiocytes (i.e. intrahepatic bile duct epithelial cells). We recently reported that a water channel, aquaporin-channel-forming integral protein of 28 kDa, is present in cholangiocytes and suggested that it plays a major role in water transport by these cells. Since the mechanisms of water transport across hepatocytes remain obscure, we performed physiological, molecular, and biochemical studies on hepatocytes to determine if they also contain water channels. Water permeability was studied by exposing isolated rat hepatocytes to buffers of different osmolarity and measuring cell volume by quantitative phase contrast, fluorescence and laser scanning confocal microscopy. Using this method, hepatocytes exposed to hypotonic buffers at 23 °C increased their cell volume in a time and osmolarity-dependent manner with an osmotic water permeability coefficient of 66.4 x 10-4 cm/s. In studies done at 10 °C, the osmotic water permeability coefficient decreased by 55% (p < 0.001, at 23 °C; t test). The derived activation energy from these studies was 12.8 kcal/mol. After incubation of hepatocytes with amphotericin B at 10 °C, the osmotic water permeability coefficient increased by 198% (p < 0.001) and the activation energy value decreased to 3.6 kcal/mol, consistent with the insertion of artificial water channels into the hepatocyte plasma membrane. Reverse transcriptase polymerase chain reaction with hepatocyte RNA as template did not produce cDNAs for three of the known water channels. Both the cholesterol content and the cholesterol/phospholipid ratio of hepatocyte plasma membranes were significantly (p < 0.005) less than those of cholangiocytes; membrane fluidity of hepatocytes estimated by measuring steady-state anisotropy was higher than that of cholangiocytes. Our data suggests that the osmotic flow of water across hepatocyte membranes occurs mainly by diffusion via the lipid bilayer (not by permeation through water channels as in cholangiocytes).

Original languageEnglish (US)
Pages (from-to)6702-6707
Number of pages6
JournalJournal of Biological Chemistry
Volume271
Issue number12
DOIs
StatePublished - Mar 22 1996

Fingerprint

Rats
Hepatocytes
Aquaporins
Water
Permeability
Hydraulic conductivity
Cell membranes
Cell Size
Osmolar Concentration
Buffers
Activation energy
Cholesterol
Cell Membrane
Membranes
Intrahepatic Bile Ducts
Membrane Fluidity
Lipid bilayers
Flow of water
Fluidity
Confocal microscopy

ASJC Scopus subject areas

  • Biochemistry

Cite this

Yano, M., Marinelli, R. A., Roberts, S. K., Balan, V., Pham, L., Tarara, J. E., ... La Russo, N. F. (1996). Rat hepatocytes transport water mainly via a non-channel-mediated pathway. Journal of Biological Chemistry, 271(12), 6702-6707. https://doi.org/10.1074/jbc.271.12.6702

Rat hepatocytes transport water mainly via a non-channel-mediated pathway. / Yano, Motoyoshi; Marinelli, Raul A.; Roberts, Stuart K.; Balan, Vijayan; Pham, Linh; Tarara, James E.; De Groen, Piet C.; La Russo, Nicholas F.

In: Journal of Biological Chemistry, Vol. 271, No. 12, 22.03.1996, p. 6702-6707.

Research output: Contribution to journalArticle

Yano, M, Marinelli, RA, Roberts, SK, Balan, V, Pham, L, Tarara, JE, De Groen, PC & La Russo, NF 1996, 'Rat hepatocytes transport water mainly via a non-channel-mediated pathway', Journal of Biological Chemistry, vol. 271, no. 12, pp. 6702-6707. https://doi.org/10.1074/jbc.271.12.6702
Yano M, Marinelli RA, Roberts SK, Balan V, Pham L, Tarara JE et al. Rat hepatocytes transport water mainly via a non-channel-mediated pathway. Journal of Biological Chemistry. 1996 Mar 22;271(12):6702-6707. https://doi.org/10.1074/jbc.271.12.6702
Yano, Motoyoshi ; Marinelli, Raul A. ; Roberts, Stuart K. ; Balan, Vijayan ; Pham, Linh ; Tarara, James E. ; De Groen, Piet C. ; La Russo, Nicholas F. / Rat hepatocytes transport water mainly via a non-channel-mediated pathway. In: Journal of Biological Chemistry. 1996 ; Vol. 271, No. 12. pp. 6702-6707.
@article{a389f519df214a95b8169d43dd4f65a4,
title = "Rat hepatocytes transport water mainly via a non-channel-mediated pathway",
abstract = "During bile formation by the liver, large volumes of water are transported across two epithelial barriers consisting of hepatocytes and cholangiocytes (i.e. intrahepatic bile duct epithelial cells). We recently reported that a water channel, aquaporin-channel-forming integral protein of 28 kDa, is present in cholangiocytes and suggested that it plays a major role in water transport by these cells. Since the mechanisms of water transport across hepatocytes remain obscure, we performed physiological, molecular, and biochemical studies on hepatocytes to determine if they also contain water channels. Water permeability was studied by exposing isolated rat hepatocytes to buffers of different osmolarity and measuring cell volume by quantitative phase contrast, fluorescence and laser scanning confocal microscopy. Using this method, hepatocytes exposed to hypotonic buffers at 23 °C increased their cell volume in a time and osmolarity-dependent manner with an osmotic water permeability coefficient of 66.4 x 10-4 cm/s. In studies done at 10 °C, the osmotic water permeability coefficient decreased by 55{\%} (p < 0.001, at 23 °C; t test). The derived activation energy from these studies was 12.8 kcal/mol. After incubation of hepatocytes with amphotericin B at 10 °C, the osmotic water permeability coefficient increased by 198{\%} (p < 0.001) and the activation energy value decreased to 3.6 kcal/mol, consistent with the insertion of artificial water channels into the hepatocyte plasma membrane. Reverse transcriptase polymerase chain reaction with hepatocyte RNA as template did not produce cDNAs for three of the known water channels. Both the cholesterol content and the cholesterol/phospholipid ratio of hepatocyte plasma membranes were significantly (p < 0.005) less than those of cholangiocytes; membrane fluidity of hepatocytes estimated by measuring steady-state anisotropy was higher than that of cholangiocytes. Our data suggests that the osmotic flow of water across hepatocyte membranes occurs mainly by diffusion via the lipid bilayer (not by permeation through water channels as in cholangiocytes).",
author = "Motoyoshi Yano and Marinelli, {Raul A.} and Roberts, {Stuart K.} and Vijayan Balan and Linh Pham and Tarara, {James E.} and {De Groen}, {Piet C.} and {La Russo}, {Nicholas F}",
year = "1996",
month = "3",
day = "22",
doi = "10.1074/jbc.271.12.6702",
language = "English (US)",
volume = "271",
pages = "6702--6707",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "12",

}

TY - JOUR

T1 - Rat hepatocytes transport water mainly via a non-channel-mediated pathway

AU - Yano, Motoyoshi

AU - Marinelli, Raul A.

AU - Roberts, Stuart K.

AU - Balan, Vijayan

AU - Pham, Linh

AU - Tarara, James E.

AU - De Groen, Piet C.

AU - La Russo, Nicholas F

PY - 1996/3/22

Y1 - 1996/3/22

N2 - During bile formation by the liver, large volumes of water are transported across two epithelial barriers consisting of hepatocytes and cholangiocytes (i.e. intrahepatic bile duct epithelial cells). We recently reported that a water channel, aquaporin-channel-forming integral protein of 28 kDa, is present in cholangiocytes and suggested that it plays a major role in water transport by these cells. Since the mechanisms of water transport across hepatocytes remain obscure, we performed physiological, molecular, and biochemical studies on hepatocytes to determine if they also contain water channels. Water permeability was studied by exposing isolated rat hepatocytes to buffers of different osmolarity and measuring cell volume by quantitative phase contrast, fluorescence and laser scanning confocal microscopy. Using this method, hepatocytes exposed to hypotonic buffers at 23 °C increased their cell volume in a time and osmolarity-dependent manner with an osmotic water permeability coefficient of 66.4 x 10-4 cm/s. In studies done at 10 °C, the osmotic water permeability coefficient decreased by 55% (p < 0.001, at 23 °C; t test). The derived activation energy from these studies was 12.8 kcal/mol. After incubation of hepatocytes with amphotericin B at 10 °C, the osmotic water permeability coefficient increased by 198% (p < 0.001) and the activation energy value decreased to 3.6 kcal/mol, consistent with the insertion of artificial water channels into the hepatocyte plasma membrane. Reverse transcriptase polymerase chain reaction with hepatocyte RNA as template did not produce cDNAs for three of the known water channels. Both the cholesterol content and the cholesterol/phospholipid ratio of hepatocyte plasma membranes were significantly (p < 0.005) less than those of cholangiocytes; membrane fluidity of hepatocytes estimated by measuring steady-state anisotropy was higher than that of cholangiocytes. Our data suggests that the osmotic flow of water across hepatocyte membranes occurs mainly by diffusion via the lipid bilayer (not by permeation through water channels as in cholangiocytes).

AB - During bile formation by the liver, large volumes of water are transported across two epithelial barriers consisting of hepatocytes and cholangiocytes (i.e. intrahepatic bile duct epithelial cells). We recently reported that a water channel, aquaporin-channel-forming integral protein of 28 kDa, is present in cholangiocytes and suggested that it plays a major role in water transport by these cells. Since the mechanisms of water transport across hepatocytes remain obscure, we performed physiological, molecular, and biochemical studies on hepatocytes to determine if they also contain water channels. Water permeability was studied by exposing isolated rat hepatocytes to buffers of different osmolarity and measuring cell volume by quantitative phase contrast, fluorescence and laser scanning confocal microscopy. Using this method, hepatocytes exposed to hypotonic buffers at 23 °C increased their cell volume in a time and osmolarity-dependent manner with an osmotic water permeability coefficient of 66.4 x 10-4 cm/s. In studies done at 10 °C, the osmotic water permeability coefficient decreased by 55% (p < 0.001, at 23 °C; t test). The derived activation energy from these studies was 12.8 kcal/mol. After incubation of hepatocytes with amphotericin B at 10 °C, the osmotic water permeability coefficient increased by 198% (p < 0.001) and the activation energy value decreased to 3.6 kcal/mol, consistent with the insertion of artificial water channels into the hepatocyte plasma membrane. Reverse transcriptase polymerase chain reaction with hepatocyte RNA as template did not produce cDNAs for three of the known water channels. Both the cholesterol content and the cholesterol/phospholipid ratio of hepatocyte plasma membranes were significantly (p < 0.005) less than those of cholangiocytes; membrane fluidity of hepatocytes estimated by measuring steady-state anisotropy was higher than that of cholangiocytes. Our data suggests that the osmotic flow of water across hepatocyte membranes occurs mainly by diffusion via the lipid bilayer (not by permeation through water channels as in cholangiocytes).

UR - http://www.scopus.com/inward/record.url?scp=0029864405&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029864405&partnerID=8YFLogxK

U2 - 10.1074/jbc.271.12.6702

DO - 10.1074/jbc.271.12.6702

M3 - Article

C2 - 8636089

AN - SCOPUS:0029864405

VL - 271

SP - 6702

EP - 6707

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 12

ER -