Differences between small and large intestine and liver in the inducibility of microsomal enzymes in response to stimulation by phenobarbitone and betanaphthoflavone in the diet

Biochem Pharmacol. 1984 Jun 15;33(12):1977-80. doi: 10.1016/0006-2952(84)90558-6.


Rats were fed either sodium phenobarbitone (PB) or betanaphthoflavone (BNF) for seven days. Deethylation of 7-ethoxyresorufin ( 7ERR ) and 7-ethoxycoumarin ( 7EC ) was measured in small and large intestine and liver, and cytochrome P-450 in liver. Our semi-purified diet was shown to produce minimal levels of intestinal deethylation activity. BNF was added to the semi purified diet and fed at levels from 0.1 to 100 mg BNF/kg of diet. Significant (P less than 0.05) induction of deethylation in small intestine was seen at all dose levels, ranging from 2-fold at 0.1 mg/kg diet to greater than 100-fold at 100 mg/kg diet. A 3-fold increase was also seen in the large intestine at 50 mg/kg. A significant increase in hepatic deethylation was only seen at 100 mg/kg. PB was administered in drinking water at 50, 100 and 1000 mg PB/l. Significant (P less than 0.05) induction of hepatic deethylation was seen at all dose levels, ranging from 2-fold at 50 mg/l to 5-fold at 1000 mg/l. Hepatic cytochrome P450 was also increased. No significant increase in intestinal deethylation was seen at any of the doses used.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 7-Alkoxycoumarin O-Dealkylase
  • Animals
  • Benzoflavones / pharmacology*
  • Cytochrome P-450 CYP1A1
  • Cytochrome P-450 Enzyme System / biosynthesis
  • Enzyme Induction / drug effects
  • Flavonoids / pharmacology*
  • Intestine, Large / enzymology*
  • Intestine, Small / enzymology*
  • Liver / enzymology*
  • Male
  • Microsomes / enzymology*
  • Mixed Function Oxygenases / biosynthesis
  • Oxidoreductases / biosynthesis
  • Oxygenases / biosynthesis
  • Phenobarbital / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • beta-Naphthoflavone


  • Benzoflavones
  • Flavonoids
  • beta-Naphthoflavone
  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • Oxidoreductases
  • Oxygenases
  • 7-Alkoxycoumarin O-Dealkylase
  • Cytochrome P-450 CYP1A1
  • Phenobarbital