Abstract
Effects of inhibiting protein kinases and phosphatases on induction of CYP2B by triphenyldioxane (TPD) and phenobarbital (PB) were investigated. Male Wistar rats were treated with test inhibitors before TPD or PB administration. Inhibitors of phosphatidylinositol-3-kinase (Wortmannin) and protein kinase C (bisindolylmaleimide I) did not have appreciable effects on TPD- or PB-induced pentoxyresorufin O-dealkylase (PROD) activity specific for CYP2B, although bisindolylmaleimide I did give substantial induction alone. W-7, an inhibitor of Ca 2+/calmodulin-dependent kinase II, produced a 6-fold increase in the TPD-induced PROD activity and did not lead to a significant increase in basal PROD activity. Treatment of rats with okadaic acid (OA), an inhibitor of protein phosphatases PP1 and PP2A, caused considerable decreases in PROD activity during the induction by TPD and PB (8- and 2.5-fold, respectively). Results of multiplex RT-PCR showed that the increase in enzymatic activity from W7 and OA treatment reflected at least in part increased mRNA levels. CYP2B mRNA level in the liver of rats treated with W-7 and TPD was 1.5 times higher than in the liver of TPD-treated rats. This effect was not observed for PB-induction. OA treatment caused a decrease of the CYP2B mRNA levels of 44% and 33% respectively, for TPD- and PB-induction. Thus, our results are consistent with the hypothesis that phosphorylation/dephosphorylation signaling pathways are involved in regulation of CYP2B induction in rat liver.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 315-322 |
| Number of pages | 8 |
| Journal | Toxicology |
| Volume | 207 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 14 2005 |
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Keywords
- Cytochrome P4502B
- Induction
- Inhibitors of protein kinases and phosphatases
- Phenobarbital
- Rat liver
- Triphenyldioxane
ASJC Scopus subject areas
- Toxicology
Cite this
In vivo effects of protein kinase and phosphatase inhibitors on CYP2B induction in rat liver. / Pustylnyak, Vladimir O.; Zakharova, Lyudmila Yu; Mikhailova, Olga N.; Rice, Robert H.; Gulyaeva, Lyudmila F.; Lyakhovich, Vyacheslav V.
In: Toxicology, Vol. 207, No. 2, 14.02.2005, p. 315-322.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - In vivo effects of protein kinase and phosphatase inhibitors on CYP2B induction in rat liver
AU - Pustylnyak, Vladimir O.
AU - Zakharova, Lyudmila Yu
AU - Mikhailova, Olga N.
AU - Rice, Robert H.
AU - Gulyaeva, Lyudmila F.
AU - Lyakhovich, Vyacheslav V.
PY - 2005/2/14
Y1 - 2005/2/14
N2 - Effects of inhibiting protein kinases and phosphatases on induction of CYP2B by triphenyldioxane (TPD) and phenobarbital (PB) were investigated. Male Wistar rats were treated with test inhibitors before TPD or PB administration. Inhibitors of phosphatidylinositol-3-kinase (Wortmannin) and protein kinase C (bisindolylmaleimide I) did not have appreciable effects on TPD- or PB-induced pentoxyresorufin O-dealkylase (PROD) activity specific for CYP2B, although bisindolylmaleimide I did give substantial induction alone. W-7, an inhibitor of Ca 2+/calmodulin-dependent kinase II, produced a 6-fold increase in the TPD-induced PROD activity and did not lead to a significant increase in basal PROD activity. Treatment of rats with okadaic acid (OA), an inhibitor of protein phosphatases PP1 and PP2A, caused considerable decreases in PROD activity during the induction by TPD and PB (8- and 2.5-fold, respectively). Results of multiplex RT-PCR showed that the increase in enzymatic activity from W7 and OA treatment reflected at least in part increased mRNA levels. CYP2B mRNA level in the liver of rats treated with W-7 and TPD was 1.5 times higher than in the liver of TPD-treated rats. This effect was not observed for PB-induction. OA treatment caused a decrease of the CYP2B mRNA levels of 44% and 33% respectively, for TPD- and PB-induction. Thus, our results are consistent with the hypothesis that phosphorylation/dephosphorylation signaling pathways are involved in regulation of CYP2B induction in rat liver.
AB - Effects of inhibiting protein kinases and phosphatases on induction of CYP2B by triphenyldioxane (TPD) and phenobarbital (PB) were investigated. Male Wistar rats were treated with test inhibitors before TPD or PB administration. Inhibitors of phosphatidylinositol-3-kinase (Wortmannin) and protein kinase C (bisindolylmaleimide I) did not have appreciable effects on TPD- or PB-induced pentoxyresorufin O-dealkylase (PROD) activity specific for CYP2B, although bisindolylmaleimide I did give substantial induction alone. W-7, an inhibitor of Ca 2+/calmodulin-dependent kinase II, produced a 6-fold increase in the TPD-induced PROD activity and did not lead to a significant increase in basal PROD activity. Treatment of rats with okadaic acid (OA), an inhibitor of protein phosphatases PP1 and PP2A, caused considerable decreases in PROD activity during the induction by TPD and PB (8- and 2.5-fold, respectively). Results of multiplex RT-PCR showed that the increase in enzymatic activity from W7 and OA treatment reflected at least in part increased mRNA levels. CYP2B mRNA level in the liver of rats treated with W-7 and TPD was 1.5 times higher than in the liver of TPD-treated rats. This effect was not observed for PB-induction. OA treatment caused a decrease of the CYP2B mRNA levels of 44% and 33% respectively, for TPD- and PB-induction. Thus, our results are consistent with the hypothesis that phosphorylation/dephosphorylation signaling pathways are involved in regulation of CYP2B induction in rat liver.
KW - Cytochrome P4502B
KW - Induction
KW - Inhibitors of protein kinases and phosphatases
KW - Phenobarbital
KW - Rat liver
KW - Triphenyldioxane
UR - http://www.scopus.com/inward/record.url?scp=10444286766&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=10444286766&partnerID=8YFLogxK
U2 - 10.1016/j.tox.2004.10.003
DO - 10.1016/j.tox.2004.10.003
M3 - Article
C2 - 15596261
AN - SCOPUS:10444286766
VL - 207
SP - 315
EP - 322
JO - Toxicology
JF - Toxicology
SN - 0300-483X
IS - 2
ER -