Figure 1.

Hyperosmolarity stimulates IL-8 production by both HT-29 (A and B) and Caco-2 (C) cells. Cells were incubated with hyperosmotic medium prepared by the addition of mannitol (A and C) or NaCl (B) to isosmolar growth medium. NaCl concentrations depicted on the x axis represent NaCl amounts added to isosmolar growth medium that already contains ∼140 mmol/L of NaCl (B). In control wells, cells were incubated with isosmolar growth medium. D: Hyperosmotic medium containing either mannitol or NaCl also stimulates GRO-α production by HT-29 cells. Supernatants for IL-8 and GRO-α measurement were taken 18 hours after the hyperosmolar challenge. Data are mean ± SEM of n = 6 to 12 wells from two different experiments. *, P < 0.05; **, P < 0.01.