Metabolism and toxicity of 2-bromo-(diglutathion-S-yl)-hydroquinone and 2-bromo-3-(glutathion-S-yl)hydroquinone in the in situ perfused rat kidney.
2-Br-(diglutathion-S-yl)hydroquinone (2-Br-(diGSyl)HQ) is a potent nephrotoxicant, causing glucosuria, enzymuria, proteinuria, elevations in blood urea nitrogen, and severe histological alterations to renal proximal tubules at doses of 10-15 mumol/kg. In contrast, 2-Br-3-(glutathion-S-yl)hydroquinone (2-Br-3-(GSyl)HQ) is substantially less nephrotoxic than 2-Br-(diGSyl)HQ and requires a dose of at least 50 mumol/kg to cause modest elevations in blood urea nitrogen concentrations. The reason or reasons for this difference in potency is unclear, but since inhibition of renal gamma-glutamyl transpeptidase (gamma-GT) prevents 2-Br-(diGSyl)HQ-mediated nephrotoxicity, metabolism of these conjugates by the kidney must play an important role. To address this question we have compared the metabolism and toxicity of 2-Br-(diGSyl)HQ and 2-Br-3-(GSyl)HQ in the in situ perfused rat kidney (ISPRK). Following infusion of 20 mumol 2-Br-3-(GSyl)HQ into the right renal artery of male Sprague Dawley rats, a total of 23.5 +/- 1.9% (mean +/- SE) of the dose was accounted for in urine and bile over a period of 180 min. 2-Bromo-3-(cystein-S-yl)hydroquinone and 2-bromo-3-(N-acetylcystein-S-yl)hydroquinone were identified in urine, and unchanged 2-Br-3-(GSyl)HQ was identified in urine and bile. The product arising from the oxidative cyclization of 2-bromo-3-(cystein-S-glycine)hydroquinone, 2H-(3-glycine)-7-hydroxy-8-bromo-1,4-benzothiazine, was also identified in urine.(ABSTRACT TRUNCATED AT 250 WORDS)
Rivera
M I
MI
Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin 78712.
Hinojosa
L M
LM
Hill
B A
BA
Lau
S S
SS
Monks
T J
TJ
D000818:Animals; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D006873:Hydroquinones / Q000378:metabolism* / Q000633:toxicity*; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007674:Kidney Diseases / Q000139:chemically induced*; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley
C090344:2-bromo-3-(glutathion-S-yl)hydroquinone; D006873:Hydroquinones; C066791:2-bromo-(diglutathion-S-yl)hydroquinone; D005978:Glutathione