Glucose‐6‐phosphate dehydrogenase and NADPH‐consuming enzymes in the rat olfactory bulb

Abstract

The resistance to oxidative stress is a multifactorial reaction involving the clustering of transcriptionally regulated genes. Because glucose-6-phosphate dehydrogenase (G6PD), the principal enzyme responsible for reducing power, is highly expressed in the olfactory bulb (OB), it is of interest to verify whether other enzymes utilizing NADPH are also highly expressed. The level and localization of G6PD- and NADPH-consuming enzymes, such as NADPH-cytochrome P450 oxidoreductase (P450R), glutathione reductase (GR), and NADPH-diaphorase (NADPH-d), were analyzed in the rat olfactory bulb (OB) by quantitative histochemistry and immunohistochemistry. The highest concentration of G6PD, P450R, and GR was observed in the olfactory nerve layer (ONL), suggesting a correlation in the expression of these enzymes at the gene level. Correlation in staining intensity between G6PD and NADPH-d activities occurred only in part of the ONL, some glomeruli, and scattered periglomerular cells. This peculiar distribution of NADPH-d could reflect a spatial patterning of the nose to bulb projections. Taken together, these results indicate that G6PD expression in the ONL could be related to the importance of generating a substantial supply of NADPH to sustain the detoxifying systems represented by GR and P450R reactions and, only in discrete zones, by NADPH-d activity.

Differential Activity of NADPH-Producing Dehydrogenases Renders Rodents Unsuitable Models to Study IDH1R132 Mutation Effects in Human Glioblastoma

“…Localization of activity of G6PDH in these mouse organs (Fig. 2) is in good agreement with previous metabolic mappings studies (Van Noorden 1984;Biagotti et al 2000;Biagotti et al 2002;Biagotti et al 2005;Ferri et al 2005). Therefore, we conclude that the concept that NADPH is mainly provided by the pentose phosphate pathway and not by IDH is based on studies of organisms other than humans.…”

Neuropathology and Neurochemistry of Nonmotor Symptoms in Parkinson's Disease

“…Although no direct information is as yet available in PD, recent studies have yielded substantial data about the molecular pathology of the olfactory bulb. Despite the relatively high content of glucose-6-phosphate dehydrogenase (G6PD), NADPH-cytochrome P450 oxidoreductase, glutathione reductase (GR) and NADPH-diaphorase (NADPH-d) in the olfactory bulb of rodents [80], significant changes in carbonylation and nitration have been found in the olfactory bulbs of old mice [81]. Targets of oxidation in aged olfactory bulbs, as revealed by redox proteomics, are aldolase 1 and ferritin heavy chain [81].…”