Murine glial cells regenerate NAD, after peroxide-induced depletion, using either nicotinic acid, nicotinamide, or quinolinic acid as substrates.
The potential for regeneration of intracellular pyridine nucleotide levels from different precursors, after peroxide-induced NAD depletion, in cultured glial cells was investigated. Cultured murine glial cells showed a decrease in intracellular NAD levels of >40% after treatment with H2O2 (100 microM). Removal of the H2O2 followed by a 2-h incubation did not result in NAD recovery in the absence of precursors. However, NAD levels increased significantly in these cells after the following substrate additions, at minimum effective concentrations of 1 mM for quinolinic acid (QUIN), 500 microM for nicotinamide, and 2 microM for nicotinic acid. The regeneration of significant amounts of NAD from nicotinic acid at doses 250 and 500 times lower than either nicotinamide or QUIN indicates a preferred route for NAD biosynthesis in glial cells in vitro, probably via nicotinic acid phosphoribosylation.
Grant
R S
RS
School of Physiology and Pharmacology, Faculty of Medicine, University of New South Wales, Sydney, Australia.
Kapoor
V
V
D000818:Animals; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D009243:NAD / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009457:Neuroglia / Q000378:metabolism*; D009525:Niacin / Q000494:pharmacology*; D009536:Niacinamide / Q000494:pharmacology*; D017378:Quinolinic Acid / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity
D009243:NAD; D009536:Niacinamide; D009525:Niacin; D006861:Hydrogen Peroxide; D017378:Quinolinic Acid