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Effects of pristane on cytochrome P450 isozyme expression in rat tissues.

Howard CB, Samuel J, Henderson SB, Stevens J, Thomas PE, Cuchens MA - Int J Environ Res Public Health (2005)

Bottom Line: Within the context of the chemical carcinogenesis model employed in this study, these observations correlated with the induction of B-cell malignancies by low doses of 3-methylcholanthrene and of thymic lymphomas by a high 3-methylcholanthrene dose.The data suggest that pristane treatment affects CYP isozyme expression.This pristane-mediated effect clearly could be a contributing factor in the chemical carcinogenesis of the previously observed lymphoid malignancies, and a possible basis for the tumor enhancing effects of pristane.

View Article: PubMed Central - PubMed

Affiliation: Breast Cancer Research Laboratory, Department of Biology, and NIH-Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, Jackson, Mississippi, USA. carolyn.b.howard@jsums.edu

ABSTRACT
Chemical carcinogenesis studies are powerful tools to obtain information on potential mechanisms of chemical factors for malignancies. In this study Western blot analyses, using monoclonal antibodies specific for three different cytochrome P450 (CYP) isozymes (CYP1A1, CYP1A2 and CYP2B), were employed to examine the effect(s) of 3-methylcholanthrene and/or pristane (2,6,10,14-tetramethylpentadecane) on the basal and inducible levels of expression of CYP proteins within Copenhagen rat tissues. Pristane exposure led to tissue specific differences in the CYP isozymes expressed and elicited increased CYP protein expression over 3-methylcholanthrene induced levels in microsomes isolated from liver, Peyer's Patches, and thymus. Within the context of the chemical carcinogenesis model employed in this study, these observations correlated with the induction of B-cell malignancies by low doses of 3-methylcholanthrene and of thymic lymphomas by a high 3-methylcholanthrene dose. The data suggest that pristane treatment affects CYP isozyme expression. This pristane-mediated effect clearly could be a contributing factor in the chemical carcinogenesis of the previously observed lymphoid malignancies, and a possible basis for the tumor enhancing effects of pristane.

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Related in: MedlinePlus

Representative Coomassie blue stained SDS-Page gel of rat Peyer’s Patches (PP), THY (T = thymus) and LIV (L = liver) microsomal proteins isolated following treatment with 3-MC (500μg dose; 12hr exposure) and with (+ = 2 wk pristine priming) or (−) without pristane. Samples were loaded at 20μg of protein/well for PP and L, or 200μg of protein/well for THY samples. Control samples (C = no 3-MC) were run in lanes next to the corresponding Tx (treatment with 500μg 3-MC directly into the PP) samples for comparison purposes as shown on the immunoblot in Fig. 7. The mobilities of molecular weight markers (MW) are indicated. Gels were electrophoresed according to the Laemmli method.
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f6-ijerph-02-00138: Representative Coomassie blue stained SDS-Page gel of rat Peyer’s Patches (PP), THY (T = thymus) and LIV (L = liver) microsomal proteins isolated following treatment with 3-MC (500μg dose; 12hr exposure) and with (+ = 2 wk pristine priming) or (−) without pristane. Samples were loaded at 20μg of protein/well for PP and L, or 200μg of protein/well for THY samples. Control samples (C = no 3-MC) were run in lanes next to the corresponding Tx (treatment with 500μg 3-MC directly into the PP) samples for comparison purposes as shown on the immunoblot in Fig. 7. The mobilities of molecular weight markers (MW) are indicated. Gels were electrophoresed according to the Laemmli method.

Mentions: Densitometric scans were employed in these studies for two purposes. One was to assure that equivalent amounts of protein were applied to each gel lane, and the other was to statistically validate any possible differences which were detected on subsequent immunoblots. One representative gel with samples from each different tissue is shown (Fig. 6), but for each group examined, four gels were run, with similar patterns emerging.


Effects of pristane on cytochrome P450 isozyme expression in rat tissues.

Howard CB, Samuel J, Henderson SB, Stevens J, Thomas PE, Cuchens MA - Int J Environ Res Public Health (2005)

Representative Coomassie blue stained SDS-Page gel of rat Peyer’s Patches (PP), THY (T = thymus) and LIV (L = liver) microsomal proteins isolated following treatment with 3-MC (500μg dose; 12hr exposure) and with (+ = 2 wk pristine priming) or (−) without pristane. Samples were loaded at 20μg of protein/well for PP and L, or 200μg of protein/well for THY samples. Control samples (C = no 3-MC) were run in lanes next to the corresponding Tx (treatment with 500μg 3-MC directly into the PP) samples for comparison purposes as shown on the immunoblot in Fig. 7. The mobilities of molecular weight markers (MW) are indicated. Gels were electrophoresed according to the Laemmli method.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814708&req=5

f6-ijerph-02-00138: Representative Coomassie blue stained SDS-Page gel of rat Peyer’s Patches (PP), THY (T = thymus) and LIV (L = liver) microsomal proteins isolated following treatment with 3-MC (500μg dose; 12hr exposure) and with (+ = 2 wk pristine priming) or (−) without pristane. Samples were loaded at 20μg of protein/well for PP and L, or 200μg of protein/well for THY samples. Control samples (C = no 3-MC) were run in lanes next to the corresponding Tx (treatment with 500μg 3-MC directly into the PP) samples for comparison purposes as shown on the immunoblot in Fig. 7. The mobilities of molecular weight markers (MW) are indicated. Gels were electrophoresed according to the Laemmli method.
Mentions: Densitometric scans were employed in these studies for two purposes. One was to assure that equivalent amounts of protein were applied to each gel lane, and the other was to statistically validate any possible differences which were detected on subsequent immunoblots. One representative gel with samples from each different tissue is shown (Fig. 6), but for each group examined, four gels were run, with similar patterns emerging.

Bottom Line: Within the context of the chemical carcinogenesis model employed in this study, these observations correlated with the induction of B-cell malignancies by low doses of 3-methylcholanthrene and of thymic lymphomas by a high 3-methylcholanthrene dose.The data suggest that pristane treatment affects CYP isozyme expression.This pristane-mediated effect clearly could be a contributing factor in the chemical carcinogenesis of the previously observed lymphoid malignancies, and a possible basis for the tumor enhancing effects of pristane.

View Article: PubMed Central - PubMed

Affiliation: Breast Cancer Research Laboratory, Department of Biology, and NIH-Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, Jackson, Mississippi, USA. carolyn.b.howard@jsums.edu

ABSTRACT
Chemical carcinogenesis studies are powerful tools to obtain information on potential mechanisms of chemical factors for malignancies. In this study Western blot analyses, using monoclonal antibodies specific for three different cytochrome P450 (CYP) isozymes (CYP1A1, CYP1A2 and CYP2B), were employed to examine the effect(s) of 3-methylcholanthrene and/or pristane (2,6,10,14-tetramethylpentadecane) on the basal and inducible levels of expression of CYP proteins within Copenhagen rat tissues. Pristane exposure led to tissue specific differences in the CYP isozymes expressed and elicited increased CYP protein expression over 3-methylcholanthrene induced levels in microsomes isolated from liver, Peyer's Patches, and thymus. Within the context of the chemical carcinogenesis model employed in this study, these observations correlated with the induction of B-cell malignancies by low doses of 3-methylcholanthrene and of thymic lymphomas by a high 3-methylcholanthrene dose. The data suggest that pristane treatment affects CYP isozyme expression. This pristane-mediated effect clearly could be a contributing factor in the chemical carcinogenesis of the previously observed lymphoid malignancies, and a possible basis for the tumor enhancing effects of pristane.

Show MeSH
Related in: MedlinePlus