title: Identification by an EPR technique of decreased mitochondrial reducing activity in puromycin aminonucleoside-induced nephrosis.
abstract: The temporal changes in the electron paramagnetic resonance (EPR) signal intensities of a nitroxide radical, 4-hydroxy 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), in the kidney in rat puromycin aminonucleoside (PAN) nephrosis were investigated in vivo and in vitro. The rats of the PAN nephrosis group received intraperitoneal injections of PAN at 75 mg/kg body weight while those of control group received saline. The in vivo renal half-lives of TEMPOL were calculated from the decay curve of EPR signal intensities after the intravenous injection of the TEMPOL solution. The mitochondrial half-lives were obtained from the decay curve of the EPR signals after mixing the mitochondrial fraction of the kidney and TEMPOL solution. The in vivo half-lives of TEMPOL of the kidney from 7 to 14 d after PAN administration were significantly longer than those of the controls. The mitochondrial half-lives of TEMPOL on the 9th day after the PAN administration prolonged remarkably compared to the controls (378 +/- 69 vs. 676 +/- 183 s, p <.01). These findings indicate that the in vivo and mitochondrial reducing activity in PAN treated rats decreased markedly, because the half-life of TEMPOL in the kidney reflects the renal reducing activity.
authors.affiliation: Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ueda
authors.forename: Sohji
authors.initials: S
authors.lastname: Nagase
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Mika
authors.initials: M
authors.lastname: Tada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ohya
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kamada
authors.forename: Aki
authors.initials: A
authors.lastname: Hirayama
authors.forename: Akio
authors.initials: A
authors.lastname: Koyama
mesh_terms: D000818:Animals; D003497:Cyclic N-Oxides / Q000493:pharmacokinetics; D004578:Electron Spin Resonance Spectroscopy; D006207:Half-Life; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008861:Microsomes / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D009401:Nephrosis / Q000139:chemically induced* / Q000378:metabolism; D010084:Oxidation-Reduction; D011507:Proteinuria / Q000139:chemically induced; D011692:Puromycin Aminonucleoside / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013113:Spin Labels
chemical_list: D003497:Cyclic N-Oxides; D013113:Spin Labels; D011692:Puromycin Aminonucleoside; C001803:tempol