Reversed transport of amino acids in Ehrlich cells.
Gramicidin induces a marked Na+-dependent efflux of amino acids from Ehrlich cells. In absence of Na+, gramicidin does not alter the efflux. In presence gramicidin, glycine efflux is inhibited by methionine and less so by leucine. Glycine efflux caused by HgCl2 is neither Na+ dependent nor inhibitable by amino acids. Neither efflux of inositol which is transported by an Na+-dependent route, nor efflux of several other solutes which are transported by Na+-independent routes, is affected by gramicidin. The antibiotic appears to permit a reversal in the direction of of the operation of the Na+-dependent amino acid transport system. The increased efflux is partly, but not entirely, due to an increase in the cellular Na+ concentration and a reduction of the electrochemical potential difference for Na+.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D006096:Gramicidin / Q000494:pharmacology; D007294:Inositol / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D012964:Sodium / Q000494:pharmacology; D013696:Temperature
D000596:Amino Acids; D006096:Gramicidin; D007294:Inositol; D012964:Sodium; D005998:Glycine