title: Hypertrophy of proximal tubular epithelial cells induced by low pH in vitro is independent of ammoniagenesis.
abstract: Metabolic acidosis can lead to tubular hypertrophy in vivo. This is thought to arise from stimulation of renal production of ammonia, a known hypertrophic agent. To examine this effect in vitro, confluent opossum (OK) proximal tubular epithelial cells were cultured at acidic pH (7.21 +/- 0.02) or at control pH (7.37 +/- 0.01) for 4 days. Protein content was 9% higher at acidic pH whereas DNA content was unaffected. The resulting increase in mean cell size (protein/DNA ratio) was 10% but correlated inversely with the mass of cells in control wells, varying from +48% at low cell mass to -14% at high cell mass. In contrast, low pH decreased 3H-thymidine incorporation by 9%. However, ammonia production was unaffected. These changes in protein/DNA ratio and 3H-thymidine incorporation cannot therefore be attributed to acid-induced ammoniagenesis and imply that low pH exerts a more direct effect on tubular cell growth than previously envisaged.
authors: Department of Nephrology, Leicester General Hospital, UK.
authors: A
authors: A
authors: Bevington
authors: C J
authors: CJ
authors: Millwater
authors: J
authors: J
authors: Walls
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D002455:Cell Division; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D006863:Hydrogen-Ion Concentration; D006984:Hypertrophy / Q000378:metabolism / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000378:metabolism* / Q000473:pathology*; D009893:Opossums; D012964:Sodium / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D014316:Tritium; D000641:Ammonia; D004247:DNA; D012964:Sodium; D013936:Thymidine