The role of intestinal microflora in the metabolic reduction of 1-nitropyrene to 1-aminopyrene in conventional and germfree rats and in humans

Cancer Lett. 1983 Jul;19(3):311-6. doi: 10.1016/0304-3835(83)90100-3.


1-Nitropyrene (100 mg/kg body wt.) was administered by gavage to conventional and germfree Fischer 344 rats. 1-Aminopyrene was detected in the feces of conventional rats (5-6% of the dose) but not in the feces of germfree rats. Conjugates of 1-aminopyrene were not detected in the feces of germfree rats and neither 1-aminopyrene nor its conjugates were found in the urine of either conventional or germfree rats. Since reduction of 1-nitropyrene to 1-aminopyrene is an activation process, the results indicate that intestinal microflora are important in the metabolic activation of 1-nitropyrene in vivo in the rat. Human intestinal microflora also reduced 1-nitropyrene to 1-aminopyrene.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anaerobiosis
  • Animals
  • Bacteria / metabolism*
  • Biotransformation
  • Feces / analysis
  • Germ-Free Life*
  • Humans
  • Intestines / microbiology*
  • Male
  • Oxidation-Reduction
  • Pyrenes / metabolism*
  • Rats
  • Rats, Inbred F344


  • Pyrenes
  • 1-aminopyrene
  • 1-nitropyrene