Effect of chronic intake of ethanol on pyridine nucleotide levels in rat liver and kidney

Abstract

Adult male Wistar rats were given ethanol in dosage forms providing either 10–12 g/kg per day for 2 weeks or 9–10 g/kg per day for 6 weeks. Pair-fed controls received equicaloric amounts of either powdered chow or sucrose in place of the alcohol. After 2 weeks, ethanol-treated rats showed a significant increase in hepatic NADH₂ concentration, a corresponding reduction in NAD concentration, and a fall in the NAD:NADH₂ ratio. NADP and NADPH₂ were not affected. After 6 weeks, total hepatic NAD + NADH₂ in ethanol-treated rats was increased, but the NADH₂ concentration remained elevated and the NAD:NADH₂ ratio depressed. No similar changes were noted in the kidney. When ethanol was withheld for 16 h before sacrifice, the total NAD + NADH₂ remained elevated but the NAD:NADH₂ ratio returned to normal. An elevated hepatic concentration of NADPH₂ and a reduced NADP: NADPH₂ ratio were also found after 6 weeks of ethanol treatment, but these changes were not reversed after 16 h withdrawal of ethanol. The administration of a test dose of ethanol (1 g/kg), after a 16-h withdrawal period, was followed by very similar changes in the hepatic NAD:NADH₂ ratio 1 and 4 h later, in ethanol-treated and control rats. Chronic ethanol treatment does not appear to produce adaptive changes leading to a more rapid reoxidation of NADH₂.