TABLE 2

PEPT1-mediated metabolism of l-CEX in permeabilized HeLa cells

Each value represents the mean ± S.E.M. (n = 3–10).

Treatment^a	Relative Activity			Corrected LDH-Cytotoxicity Ratio^d
Treatment^a		l-CEX Metabolism^b	d-CEX Uptake^c	Corrected LDH-Cytotoxicity Ratio^d
	% of control			%
Control	100 ± 11.7	100 ± 6.0	99.6 ± 3.8
Hypotonic	27.7 ± 9.2	9.5 ± 2.6	25.9 ± 2.7
Digitonin	49.4 ± 12.2	8.4 ± 18.1	6.9 ± 4.9

↵ a Cells were pretreated with hypotonic or digitonin (125 μg/ml) solution.
↵ b Data were obtained by subtracting the metabolism of l-CEX (28.8 μM) for 180 min at pH 6.0 in mock from that in HeLa/PEPT1 cells.
↵ c Data were obtained by subtracting the uptake of d-CEX (28.8 μM) for 180 min at pH 6.0 in mock from that in HeLa/PEPT1 cells.
↵ d LDH activity is shown as corrected LDH-cytotoxicity ratio, obtained by using the equation 100 — LDH-cytotoxicity ratio.