Figure 2

Dose-response curves for putrescine and cadaverine in HT29 intestinal cells. Cell cultures were exposed to a range of putrescine (A) or cadaverine (B) concentrations for 24 h. The curves were made by plotting the normalized cell index at 24 h of treatment obtained using RTCA, against the log₁₀ value of the corresponding BA concentration. The data represent the means ± standard deviations of at least three independent experiments. An asterisk indicates the first significant difference with respect to the smallest dose of BA assayed (0.63 mM for both putrescine and cadaverine); it therefore corresponds to the LOAEL  (*p < 0.05). Numerical values for the IC₅₀, NOAEL, LOAEL, Hill slope and R² are also indicated.