Influence of ethanol, nicotinamide, orotic acid and caffeine upon the induction of tyrosine aminotransferase, the NAD content and the ADPR transferase activity in rat liver.
Chronic uptake of ethanol leads to irreversible damage of liver cells. Until now the cause of this alteration is unknown. To get more information experiments presented in this paper were performed. Contrary to normal fed animals the enzyme tyrosine aminotransferase (TAT) can be induced by ethanol in starved rats. Orotic acid induces the TAT at a dose of 500 mg/kg. This effect is enhanced to some extent by ethanol. Ethanol increases the minor effect of 50 mg/kg caffeine on TAT induction markedly. Only 500 mg/kg nicotinamide (NA) enhances TAT activity. Here ethanol has a minor stimulatory effect. A combination of nicotinamide with orotic acid or with caffeine leads to substances with a higher effect on TAT induction. Besides nicotinamide and its derivatives only caffeine changes the NAD+ + NADH content of the liver. Ethanol and caffeine reduce the activity of the ADPR transferase. The results indicate that the effect of ethanol might be due to interference with NAD-adenoribosylation metabolism.
Kröger
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H
Grätz
R
R
Grahn
H
H
D000315:Adrenalectomy; D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D008099:Liver / Q000032:analysis / Q000187:drug effects* / Q000201:enzymology; D009243:NAD / Q000032:analysis; D009536:Niacinamide / Q000494:pharmacology*; D009713:Nucleotidyltransferases / Q000032:analysis*; D009963:Orotic Acid / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases; D051381:Rats; D011919:Rats, Inbred Strains; D014444:Tyrosine Transaminase / Q000096:biosynthesis*
D009243:NAD; D009536:Niacinamide; D002110:Caffeine; D000431:Ethanol; D009963:Orotic Acid; D011065:Poly(ADP-ribose) Polymerases; D014444:Tyrosine Transaminase; D009713:Nucleotidyltransferases