Extraction and analysis of superoxide free radicals (·O⁻₂) from whole mammalian liver

Abstract

Extraction of whole lobes of normal rat liver with dimethyl sulphoxide (DMSO) under N2 gives extracts which contain 5-10 mumol/l.O2- (50-100 nmol.O2- per 10 ml extract per 4 g liver; 1.25-2.50 nmol.O2- per millilitre per gram liver). Evidence for .O2- in the extracts is given by: (1) electron spin resonance signals (ESR), (2) differential pulse polarography (DPP), (3) chemiluminescence (CL), and (4) nitroblue tetrazolium reduction (NBT). All tests yield results identical with those obtained with authentic .O2-. Extraction of .O2- is enhanced by tetrabutyl ammonium ion, and is maximal at 1-3 min. These results raise the possibility that substantial amounts of .O2- are normally sequestered in protective membranous sites in vivo.

Reactive Oxygen Species—(ROS) Pathogens or Sources of Vital Energy? Part 1. ROS in Normal and Pathologic Physiology of Living Systems

“…In some plants, a nearly complete blocking of mitochondrial respiration lessens O 2 consumption only by 5%-30%. 44 Intact animal organs and tissues use at least 10%-15% of all oxygen consumed by them to generate ROS, 45 and, in intact segments of rat aorta, up to 26% of oxygen is directly reduced to superoxide. 46 Even more oxygen is routed on one-electron reduction in developing embryos.…”

Water and the Cell

“…Only by the stage of blastocysts this share decreases to 30%, however, not at the expense of diminution of direct O 2 reduction, but due to increase in mitochondrial respiration (Trimarchi et al, 2000). Many adult animal organs and tissues use at least 10-15% of all oxygen for generation of ROS (Shoaf et al, 1991), while in intact segments of rat aorta up to 26% of oxygen is directly reduced to superoxide (Souza et al, 2002). White blood cells as well as platelets are actively respiring, and superoxide generation continuously proceeds in whole blood of healthy donors (Voeikov and Novikov, 1997).…”