Fig. 7. Effect of hydrocortisone on tight junction function in EpH4 cells grown on Transwell filters. Hydrocortisone (5 µmol/l; HC) was added to the culture medium where indicated. (A) The TER was measured daily in treated and untreated cultures. (B) At the indicated times [3H]mannitol was added to the top well; 5 hours later a sample was taken from the top and bottom well, counted, and the percentage of isotope passing from the top to the bottom chamber was calculated.