Salicylate-promoted permeation of cefoxitin, insulin and phenylalanine across red cell membrane. Possible mechanism.

Uptake of sodium cefoxitin, D-phenylalanine and insulin into human red blood cells was significantly enhanced by the presence of salicylate and 5-methoxysalicylate in the medium. The mechanism of adjuvant action appeared to depend on an affinity between the adjuvant and the protein fraction in the erythrocyte membrane. The inhibitory effect of DIDS and phlorizin on the salicylate-enhanced uptake of these compounds strongly suggests that the ability of salicylate to permeate the membrane may be essential for it to act as an adjuvant.