H+ gradient-dependent transport of aminocephalosporins in rat renal brush border membrane vesicles: role of H+/organic cation antiport system
Inui, K.; Takano, M.; Okano, T.; Hori, R.
Journal of Pharmacology and Experimental Therapeutics 233(1): 181-185
1985
ISSN/ISBN: 0022-3565 PMID: 2984412 Document Number: 253555
The transport of aminocephalosporin antibiotics such as cephalexin, zwitterion, by rat renal brush border membrane vesicles has been studied in relation to the transport system of organic cation. Cephalexin uptake was inhibited by organic cations such as tetraethylammonium, 1N-methylnicotinamide and choline, whereas cefazolin uptake was not. Tetraethylammonium uptake was inhibited by aminocephalosporins and stimulated by the countertransport effect of cephalexin. In agreement with the transport mechanisms of organic cation, the presence of an H+ gradient ([H+]i greater than [H+]o) induced a marked stimulation of aminocephalosporin uptake, and this uptake was inhibited by HgCl2 and tetraethylammonium. These results suggest that aminocephalosporins can share a common carrier transport system with organic cation in renal brush border membranes, and this system could be a part of the mechanisms of tubular secretion for aminocephalosporins.