The effects of salicylate concentration on the uptake of salicylate and cefmetazole into rat isolated small intestinal epithelial cells.

The uptake of salicylate into rat isolated small intestinal epithelial cells reached an equilibrium within 15 min, but that of cefmetazole alone did not. The presence of salicylate at concentrations greater than 50 mM accelerated the uptake of cefmetazole, which reached equilibrium within 5 min. At equilibrium, the uptake clearance of salicylate (mumol (g protein)-1 M-1 initial salicylate concn) was greater than that of cefmetazole. The uptake clearance of salicylate during the first several minutes was concentration-dependent, and a 'super-uptake' clearance of salicylate, greater than equilibrium values, was observed when 100 mM salicylate was present. This indicates that some mechanism, other than a simple diffusion process, may be involved in salicylate uptake into these cells.