Breed and species comparison of amino acid transport variation in equine erythrocytes.
The amino acid permeability of red blood cells from Equus caballus (thoroughbred, Arab, shire and pony), E przewalskii (Przewalski's horse), E asinus (donkey and mule) and E burchelli (common or plains zebra) was measured. Individual animals exhibited stable but widely differing rates of L-[U-14C]alanine uptake in the range 5 to 1554 mumol (litre cells)-1 h-1 (0.2 mM extracellular L-alanine, 37 degrees C). Of the thoroughbreds tested, 30 per cent had red blood cells which were essentially impermeable to L-alanine (5 to 10 mumol (litre cells)-1 h-1, giving transport rates similar to those found previously in amino acid transport-deficient sheep erythrocytes. In contrast, only 3 per cent of the ponies tested had red blood cells impermeable to L-alanine. No cases of erythrocyte amino acid transport deficiency were found in the other horse breeds and species tested.
D000409:Alanine / Q000097:blood; D000596:Amino Acids / Q000097:blood*; D000818:Animals; D002250:Carbon Radioisotopes; D002463:Cell Membrane Permeability; D004912:Erythrocytes / Q000378:metabolism*; D006736:Horses / Q000097:blood* / Q000235:genetics; D010527:Perissodactyla / Q000097:blood*; D013045:Species Specificity; D013237:Stereoisomerism
D000596:Amino Acids; D002250:Carbon Radioisotopes; D000409:Alanine