Alloxan-induced luminol luminescence as a tool for investigating mechanisms of radical-mediated diabetogenicity

Abstract

Chemiluminescence of luminol in a cell-free system was used to investigate the mechanism of alloxan-dependent free-radical generation. In the presence of alloxan and reduced glutathione (GSH), luminescence was greatly stimulated by FeSO4. Replacing GSH by oxidized glutathione or NAD(P)(H), or replacing FeSO4 by CuSO4, ZNSO4 or FeCl3, did not yield chemiluminescence. The chemiluminescence of a mixture of alloxan. GSH, FeSO4 and luminol was inhibited by catalase, superoxide dismutase, scavengers of hydroxyl radicals (sodium benzoate, n-butanol, D-mannitol, dimethyl sulphoxide) or metal-ion chelators (EDTA, diethylenetriaminepenta-acetic acid, diethyldithiocarbamate. desferroxamine), D-glucose, L-glucose, D-mannose, D-fructose, 3-O-methyl-D-glucose, NAD+, NADH, NADP+ or NADPH, but not by urea or enzymically inactive superoxide dismutase. The results support the hypothesis that the diabetogenic action of alloxan is mediated by hydroxyl radicals generated in an iron-catalysed reaction. Protection against alloxan in vivo depends both on the chemical reactivity of protector with radicals or radical-generating systems and on the stereospecific requirement of some strategic site in the B-cell.

Evidence for reactive oxygen intermediates causing hemolysis and parasite death in malaria

“…From other reports of the use of desferrioxamine (21), DDC (19), and propanol (23) in conjunction with alloxan, our results with these agents (Fig. 2 and 3) were consistent with the alloxan-induced hemolysis and parasite death being caused by reactive oxygen species, probably hydroxyl radicals.…”

Enhancement by streptozotocin of O−2 radical generation by the xanthine oxidase system of pancreatic β‐cells

“…Their mechanisms of action are unknown, but since their actions are inhibited by superoxide dismutase (SOD) [4,5] or a chemical scavenger, such as 1,1-dimethylurea [6], they have been suggested to be related to the formation of free radicals. In fact, some reports strongly support the participation of free radicals in the action of alloxan [7,8]. In this work, we investigated the relation between the action of STZ on &cells and their generation of free radicals, measured by electron spin resonance (ESR) spectrometry.…”

Silk fibroin has a protective effect against high glucose induced apoptosis in HIT‐T15 cells

“…Treatment with super oxide dismutase (SOD) prevents alloxan-induced diabetes in mice [11]. Several investigators have also shown that hyperglycemia induces ROS and causes oxidative stress [12][13][14][15][16][17].…”