Lysine transport in lactating rat mammary tissue: evidence for an interaction between cationic and neutral amino acids.

The transport of lysine by the lactating rat mammary gland has been examined to determine whether there is an interaction between cationic and neutral amino acids. Lysine uptake was time dependent and unaffected by replacing Na + with choline. In the presence of Na + , lysine influx was inhibited by cationic amino acids (arginine, homoarginine, ornithine and lysine) and by a range of neutral amino acids (methionine, glutamine, leucine, phenylalanine, alanine, asparagine, α-aminoisobutyric acid (AIB), 2-aminobicyclo [2,2,1] heptane-2-carboxyIic acid (BCH), proline and tryptophan)