Effects of methylguanidine on sodium and organic ion transport.
We studied the acute effect of methylguanidine (MG), a suspected uremic toxin that accumulates in renal failure, on p-aminohippurate (PAH) and tetraethylammonium (TEA) uptake in rabbit kidney slices, on Na+,K+ ATPase activity in the microsomal fraction of rabbit kidneys, and on transepithelial active Na transport across toad skin. MG at concentrations ranging from 0.05 (similar to that reported in uremic patients) to 1.0 mM does not affect the organic anion (PAH) uptake, although it exhibits a concentration-dependent inhibition of organic cation (TEA) uptake. MG at concentrations from 0.05 to 5 mM had no effect on kidney Na+,K+ ATPase activity or on active transepithelial Na transport across toad skins when applied to the outside bathing solution; however, MG (greater than 1 mM) stimulated Na transport when applied to the inside bathing solution. These results are not consistent with the hypothesis that MG is a potential uremic toxin that causes the natriuresis and other toxic effects. However, long-term toxic effects of MG on the kidney were not assessed in the present study.
Li
M
M
Department of Physiology, State University of New York, Buffalo 14214.
Chung
S T
ST
Hong
S K
SK
Goldinger
J M
JM
D000704:Analysis of Variance; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002024:Bufo marinus; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008760:Methylguanidine / Q000494:pharmacology*; D011817:Rabbits; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D012984:Software; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000378:metabolism*; D010130:p-Aminohippuric Acid / Q000378:metabolism*
D013757:Tetraethylammonium Compounds; D008760:Methylguanidine; D019789:Tetraethylammonium; D012964:Sodium; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D010130:p-Aminohippuric Acid