Induction of xenobiotic-metabolizing enzymes in hepatocytes by beta-naphthoflavone: Time-dependent changes in activities, protein and mRNA levels

Abstract

In the present study, time-dependency of the induction effect of a selective inducer on the activity, protein and mRNA levels of cytochromes P450 1A1/2 (CYP1A1/2), NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferases (GSTA), in primary culture of rat hepatocytes was tested and evaluated. To show the differences in responses of tested enzymes, the common aryl hydrocarbon receptor (AhR) ligand agonist, beta-naphthoflavone (BNF), was used. Induction of CYP1A1/2 by BNF was detected at all time intervals and at all levels (i.e., mRNA, protein, enzyme activity). Different responses of NQO1 and GSTA upon BNF treatment were observed. Our results demonstrate that the responses of different xenobiotic-metabolizing enzymes to the inducer vary in time and depend on the measured parameter. For these reasons, an induction study featuring only one-time interval treatment and/ or one parameter testing could produce misleading information.

Sub-lethal doses of albendazole induce drug metabolizing enzymes and increase albendazole deactivation in Haemonchus contortus adults

“…Although induced expression of certain DMEs in resistant isolates in comparison to sensitive ones has been reported repeatedly [5,6,12,14], the mechanisms and circumstances of this induction have not been elucidated. As the contact of nematodes with sub-lethal doses of anthelmintics may play an important role, we incubated ex vivo H. contortus adults from ISE strain (sensitive to all anthelmintics) with the anthelmintic drug albendazole (ABZ) and its active metabolite ABZ-sulfoxide (ABZSO) at three sub-lethal doses for 4 and 12 h. Two different incubation duration were used because it is known that the time required to induce different DMEs differs significantly [29]. The expression levels of individual CYPs, UGTs and P-gps were quantified and compared to levels in controls (exposed to solvent only).…”

The Modulation of Phase II Drug-Metabolizing Enzymes in Proliferating and Differentiated CaCo-2 Cells by Hop-Derived Prenylflavonoids

“…A substantially low correlation between the enzymatic activity and mRNA expression of GSTA and NQO1 has been reported in primary rat hepatocytes treated with the prototypical aryl hydrocarbon receptor agonist β-naphthoflavone. On the other hand, a good correlation between those two parameters has been found in the case of CYP1A1/2 [44]. Taking a pharmacological/toxicological viewpoint into consideration, enzymatic activity is the most important indicator of a compound's effect, as it ultimately affects the clearance of a metabolized drug [45].…”

The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part I: Isolation, structural, genetic, and biochemical characterization

“…The increase in CYP 1A1/1A2 catalytic enzyme activity (i.e., ~twofold) is relatively modest, but the fold‐increase is similar to what has been observed in BaP‐induced pUR288 lacZ plasmid mouse hepatocytes (i.e., ~fivefold) (Zwart et al, ). The EROD activity observed in β‐naphthoflavone‐induced primary MutaMouse hepatocytes is ~100‐fold higher than that observed in β‐naphthoflavone‐induced rat primary hepatocytes (Lnenikova et al, ). In addition, the ~twofold induction in CYP1A1/1A2 and CYP2B activity observed in MutaMouse primary hepatocytes following exposures to β‐naphthoflavone and phenobarbital, respectively, is similarly observed in HepaRG cells (Wang et al, ).…”