title: Cadmium inhibition of L-alanine transport into renal brush border membrane vesicles isolated from the winter flounder (Pseudopleuronectes americanus).
abstract: Using isolated brush border membrane vesicles from the kidney of the winter flounder (Pseudopleuronectes americanus), we have studied the effect of cadmium on L-alanine transport. Pretreatment of vesicles with 0.1 mM Cd2+ resulted in inhibition of L-alanine uptake in the presence of a NaCl (but not KCl) gradient. Inhibition was due to a specific interaction with the sodium-alanine cotransport system and not a change in the driving forces for alanine transport, since Cd2+ did not affect sodium-dependent D-glucose uptake. The effect of Cd2+ on Na+-alanine cotransport showed mixed-type inhibition which is only partially reversible by EDTA. Cd2+ uptake itself was shown to be time and temperature dependent, resulting in binding to both sides of the membrane. No direct correlation was possible between inhibition of L-alanine transport and the amount of Cd2+ taken up by the membranes. Nevertheless, the striking time dependence of the effect of Cd2+ on sodium-dependent L-alanine uptake and the inability of EDTA to reverse the inhibitory action of Cd2+ suggest that Cd2+ inhibits Na+-alanine cotransport at the cytoplasmic side of the membrane.
authors.affiliation: Max-Planck-Institut für Systemphysiologie, Dortmund, Federal Republic of Germany.
authors.forename: C
authors.initials: C
authors.lastname: Bevan
authors.forename: E
authors.initials: E
authors.lastname: Kinne-Saffran
authors.forename: E C
authors.initials: EC
authors.lastname: Foulkes
authors.forename: R K
authors.initials: RK
authors.lastname: Kinne
mesh_terms: D000409:Alanine / Q000378:metabolism* / Q000493:pharmacokinetics; D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002104:Cadmium / Q000633:toxicity*; D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D005432:Flounder / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008871:Microvilli / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D027981:Symporters; D014873:Water Pollutants / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D002352:Carrier Proteins; D027981:Symporters; D014873:Water Pollutants; D014874:Water Pollutants, Chemical; C052168:sodium-alanine cotransporter; D002104:Cadmium; D012964:Sodium; D000409:Alanine