FIGURE 9.

Effect of silencing ZAC1 expression on sorbitol accumulation under hypertonic stress. A, intracellular sorbitol concentration in IMCD3 cells chronically adapted to increasing levels of tonicity (600 and 900 mosmol/kg H₂O) showing a substantial accumulation under hypertonic stress. B, intracellular sorbitol concentration (microtiter plate assay) in ZAC1-silenced clones compared with empty vector controls. No significant change is observed between clones and empty vector control cells at isotonic conditions (300 mosmol/kg H₂O). However, under acute hypertonic stress (550 mosmol/kg H₂O for 48 h), levels of intracellular sorbitol are dramatically reduced as a consequence of silencing ZAC1 expression.