Characteristics of lysine transport by isolated rat renal cortical tubule fragments.
The uptake of L-lysine was examined in isolated renal cortical tubules. Lysine was actively taken up by the renal tubule cells isolated from 7-week-old rats. No metabolism of the transported lysine was found. There was no evidence for sodium-dependence of lysine uptake. Concentration dependence studies revealed that the lysine was taken up by one saturable transport system with a Km of 1.66 mmol/l and Vmax of 7 mmol/l intracellular fluid per 10 min. Lysine also entered by a non-saturable pathway. Arginine and ornithine inhibited the initial uptake of lysine. Cystine increased the efflux of lysine from preloaded renal cells via hetero-exchange, indicating that a common system exists for these two amino acids.
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D003553:Cystine / Q000494:pharmacology; D007672:Kidney Cortex / Q000378:metabolism*; D007684:Kidney Tubules / Q000378:metabolism*; D007700:Kinetics; D008239:Lysine / Q000378:metabolism*; D009952:Ornithine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology
D003553:Cystine; D001120:Arginine; D012964:Sodium; D009952:Ornithine; D008239:Lysine