Abstract
Interactions between cationic and neutral amino acids in transport across the brush-border membrane, J mc , of the small intestine have been examined using preparations from the distal rabbit ileum and the rat and guinea-pig mid-small intestine. (1) In the guinea pig, the dependence of J mc Lys on the concentration of lysine is best described in terms of two saturable transport mechanisms in addition to free diffusion. (2) It is shown that the discrepancy between cis-effects of low concentrations of neutral amino acids on the J mc of cationic amino acids, cis-stimulation in the guinea pig contra cis-inhibition in the rabbit and rat, represents species differences. In the guinea pig, imposing sodium-free conditions turns cis-stimulation into cis-inhibition. (3) It is demonstrated that in rat and guinea pig, leucine is transported both by the transport system(s) for cationic amino acids and by transport system(s) which cannot be inhibited by cationic amino acids.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
