Induction of rat kidney ornithine decarboxylase by nicotinamide without a concomitant increase in DNA synthesis.
Four hours after an i.p. injection of 500 mg/kg nicotinamide, there was a decrease in kidney ODC activity, followed by a substantial increase by 24 h. Exposing rats to 0, 0.67, 6.7 and 30 mM nicotinamide in their drinking water for 7 and 28 days also resulted in a statistically significant increase in kidney ODC activity, but the rates of DNA synthesis were unaffected, as measured by incorporation of [3H]thymidine into DNA and % labeled proximal tubule nuclei; the total amount of DNA/kidney was also unaffected. The results of this investigation demonstrate that nicotinamide, a known renal tumor promoter, was able to induce a significant increase in ODC activity in the rat kidney without a concomitant increase in DNA synthesis, suggesting that early stimulation of ODC is associated with tumor promotion even in the absence of effects on DNA replication.
D000818:Animals; D004261:DNA Replication / Q000187:drug effects*; D004790:Enzyme Induction; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009536:Niacinamide / Q000494:pharmacology*; D009955:Ornithine Decarboxylase / Q000096:biosynthesis*; D051381:Rats; D011916:Rats, Inbred F344
D009536:Niacinamide; D009955:Ornithine Decarboxylase