Table 3.

Effect of various potential inhibitors on l-lactate uptake into pig colonic LMV

Inhibitor	l-Lactate uptake
	(pmol (mg protein)−1 (5 s)−1)	% control
Control	301 ± 8	100
pCMBS	111 ± 2	37*
pCMB	202 ± 13	60*
HgCl2	172 ± 7	57*
Mersalyl acid	54 ± 3	18*
Phloretin	136 ± 7	45*
NPPB	160 ± 6	53*
DEPC	202 ± 6	67*
DIDS	295 ± 10	98
SITS	280 ± 2	93

LMV were preloaded with the standard loading buffer (100 mm mannitol, 100 mm sodium l-lactate, 0.1 mm MgSO₄, and 20 mm Hepes-Tris, pH 7.5) as described in Methods. Membrane vesicles (100 μg of protein per assay) were incubated for 30 min at 4 °C with the indicated compounds. Mercurials (pCMBS, pCMB, HgCl₂, mersalyl acid), NPPB, and phloretin were added to a volume of vesicles to give a final concentration of 0.5 mm, whilst the final concentrations of diethylpyrocarbonate (DEPC), DIDS, SITS amounted to 1 mm. LMV (control) were incubated at 4 °C for 30 min. l-Lactate uptake by pretreated and control LMV was measured at 37 °C for 5 s in the standard uptake buffer (see Table 2). Values are presented as means ±s.e.m. for three experiments.

^*Statistically significant (P < 0.05) from control.