title: Cell volume regulation of rabbit cortical collecting tubule in anisotonic media.
abstract: Volume regulation of nonperfused rabbit cortical collecting tubules in anisotonic bathing media was examined in vitro. When media osmolality is abruptly increased by 150 mosmol/kgH2O with the addition of NaCl, tubules shrink by 20% but do not volume regulate. However, volume regulatory increase (VRI) is observed when 1 mM butyrate is present in the bathing media or when tubules are pretreated with hypotonic media. When media osmolality is increased, butyrate-treated tubules shrink to 74% of their isotonic control volume. As evidence of volume regulation, butyrate-treated tubules swell while still bathed in hypertonic media, recovering in 30 min 78% of the volume lost due to osmotic shrinkage. The butyrate effect requires external Na+ and is inhibited by amiloride. When media osmolality is lowered to 150 mosmol/kgH2O, nonbutyrate tubules swell before showing typical volume regulatory decrease. When these tubules are returned to isotonic media, they immediately shrink to 78% of control volume before showing evidence of VRI. These results suggest that, under the appropriate conditions, cortical collecting tubules are capable of VRI.
authors.affiliation: Department of Medicine/Nephrology, Winthrop-University Hospital, Mineola, New York 11501.
authors.forename: E
authors.initials: E
authors.lastname: Natke
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002021:Buffers; D002087:Butyrates / Q000037:antagonists & inhibitors / Q000494:pharmacology; D020148:Butyric Acid; D003470:Culture Media; D007038:Hypotonic Solutions; D007552:Isotonic Solutions; D007672:Kidney Cortex; D007684:Kidney Tubules / Q000166:cytology*; D007685:Kidney Tubules, Collecting / Q000166:cytology*; D009995:Osmosis; D011817:Rabbits; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D014508:Urea / Q000494:pharmacology
chemical_list: D001639:Bicarbonates; D002021:Buffers; D002087:Butyrates; D003470:Culture Media; D007038:Hypotonic Solutions; D007552:Isotonic Solutions; D012462:Saline Solution, Hypertonic; D020148:Butyric Acid; D000584:Amiloride; D014508:Urea; D012964:Sodium