FIG. 2.

TDH influences calcium homeostasis in IEC-6 cells. (a) Cells treated with 2.5 HU of TDH per ml; (b) cells exposed to 1 mM EGTA for 20 min before TDH treatment; (c) cells exposed to TDH for 30 min and then washed. Graphs show the first 40 min of the experiments. After the rapid increase in intracellular calcium level, the decrease occurs between 5 and 25 min (a and c). The y axis represents the ratio 340/380. The negative deflection at about 5 min represents an artifact due to the closure of the shutter to expose the dish and check whether the TDH was added correctly. The rise in cytosolic Ca²⁺ level is transient, totally reversible, and prevented by EGTA. ↓, TDH addition; ↑, washing.