Hepatocytes volume regulation.
Cell volume regulation has been studied during isolated dog liver perfusion. In presence of ouabain (10(-4) M) rapid but quantitatively matched exchange of K for Na occurs and the cellular volume is maintained until (90 min later) intracellular K concentration falls below 80 mEq/litre. Additional mechanism of protection of cell volume as loss of intracellular anions should also play a rôle since ouabain produces rapidly a membrane depolarization and chloride gain. A similar sequence of events is obtained when inhibition of the sodium pump is produced by anoxia but in this case the chloride gain in excess of cation gain is particularly marked. Submitted to an hypotonic shock the hepatocytes swell but tend to partially recover their volume by loosing K, indeed when osmolarity is corrected the cells maintain a sub-normal volume. Ouabain inhibits (or masks?) this iso-osmotic regulation. When submitted to an hypertonic medium a reduced cell volume is obtained and maintained for hours even in presence of ouabain, which produces a Na/K exchange at the same rate as in normal conditions.
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Lambotte
D000818:Animals; D004285:Dogs; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000166:cytology* / Q000187:drug effects; D009994:Osmolar Concentration; D010042:Ouabain / Q000494:pharmacology; D010477:Perfusion; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism
D010042:Ouabain; D012964:Sodium; D011188:Potassium