title: Uptake of aminoglycoside antibiotics into brush-border membrane vesicles and inhibition of (Na+ + K+)-ATPase activity of basolateral membrane.
abstract: The effects of aminoglycoside antibiotics on plasma membranes were studied using rat renal basolateral and brush-border membrane vesicles. 3',4'-Dideoxykanamycin was bound to the basolateral membrane and brush-border membrane vesicles. They had a single class of binding sites with nearly the same constant, and the basolateral membrane vesicles had more binding sites than those of the brush-border membrane. Dideoxykanamycin B was transported into the intravesicular space of brush-border membrane vesicles, but not into that of basolateral membrane vesicles. The (Na+ + K+)-ATPase activity of the plasma membrane fraction prepared from the kidney of rat administered with dideoxykanamycin B intravenously decreased significantly. Aminoglycoside antibiotics entrapped in the basolateral membrane vesicles inhibited (Na+ + K+)-ATPase activity, but those added to the basolateral membrane vesicles externally failed to do so. The activity of (Na+ + K+)-ATPase was non-competitively inhibited by gentamicin. It is thus concluded that aminoglycoside antibiotics are taken up into the renal proximal tubular cells across the brush-border membrane and inhibit the (Na+ + K+)-ATPase activity of basolateral membrane. This inhibition may possibly disrupt the balance of cellular electrolytes, leading to a cellular dysfunction, and consequently to the development of aminoglycoside antibiotics' nephrotoxicity.
mesh_terms: D000617:Aminoglycosides / Q000378:metabolism / Q000633:toxicity; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000633:toxicity; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D003982:Dibekacin / Q000378:metabolism / Q000633:toxicity; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D010743:Phospholipids / Q000032:analysis; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D010743:Phospholipids; D003982:Dibekacin; D000254:Sodium-Potassium-Exchanging ATPase