Evidence for an interaction between cationic and neutral amino acids at the blood-facing aspect of the lactating rat mammary epithelium.
The transport of lysine by perfused lactating rat mammary tissue has been examined using a rapid, paired-tracer dilution technique. This experimental approach allowed the characteristics of lysine transport across the blood-facing aspect of the mammary epithelium to be studied. The clearance of lysine from the perfusate was influenced by the extracellular lysine concentration in a fashion consistent with the presence of carrier-mediated transport. Replacing extracellular Na+ with N-methyl-D-glucamine had no significant effect on lysine transport. Lysine uptake was inhibited by extracellular leucine and glutamine but not by alpha-(methylamino)isobutyric acid. Leucine interacted with lysine transport under Na+(-)free conditions. It appears that the system for cationic acid transport which is situated in the blood-facing aspect of the lactating rat mammary epithelium may also accept neutral amino acids as substrates.
Calvert
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DT
Hannah Research Institute, UK.
Shennan
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DB
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002412:Cations; D004848:Epithelium / Q000378:metabolism; D005260:Female; D005973:Glutamine / Q000494:pharmacology; D007700:Kinetics; D007774:Lactation / Q000502:physiology*; D007930:Leucine / Q000494:pharmacology; D008239:Lysine / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015091:beta-Alanine / Q000031:analogs & derivatives / Q000494:pharmacology
D000596:Amino Acids; D002412:Cations; D005973:Glutamine; D015091:beta-Alanine; C012924:2,2-dimethyl-beta-alanine; D007930:Leucine; D008239:Lysine