Changes in endoplasmic reticulum associated with beta-naphthoflavone-inducible cytochrome P450 in murine liver: a...

Cytochrome P450s are found associated with membranes of endoplasmic reticulum where they catalyse the oxidation and biotransformation of a wide range of substances. It is therefore expected that their induction and catalytic activities would correlate with the ultrastructure of the cell. In this study, we compared the structure of the hepatocytes of C57BL/6 mice at the basal level in the untreated control animal, and followed induction with the beta-naphthoflavone in the experimental animal. Qualitative analysis of liver sections from control, corn oil-treated mice, and the induced, beta-naphthoflavone-treated mice were essentially similar with no obvious differences between the two groups. Direct morphometry was utilized to quantify the amounts of smooth and rough endoplasmic reticulum in the hepatocytes. A computerized Bioquant Image Analysis System was used to determine the areas of endoplasmic reticulum in the hepatocytes. Morphometric analysis showed 1.004-fold increase in the amount of smooth endoplasmic reticulum and 1.018-fold increase in amount of rough endoplasmic reticulum following treatment of C57BL/6 mice with beta-naphthoflavone. These increases were not significantly different from amounts in control hepatocytes (P). In conclusion, induction of cytochrome P450 by beta-naphthoflavone does not appear to elicit increased proliferation of the endoplasmic reticulum.