ISSN:
1432-0738
Keywords:
Polychlorinated biphenyls
;
2,2′,3,3′,6,6′-hexachlorobiphenyl
;
2,2′,4,4′,5,5′-hexachlorobiphenyl
;
Cytochrome P450 isoenzymes
;
Enzyme induction
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Tissue distribution and effects induced by 2,2′,4,4′,5,5′-hexachlorobiphenyl (245-HCB) on cytochrome P450 isozymes were compared with those of 2,2′,3,3′,6,6′-hexachlorobiphenyl (236-HCB). Male Wistar rats were given a single intragastric dose (23 mg/kg body wt) of either isomer, and killed after 72 h. At termination the tissue concentrations of 245-HCB were considerably higher than those of 236-HCB, suggesting a more effective metabolism of the latter. The binding affinity of 236-HCB to cytochrome P450 was higher and the magnitude of binding greater than of 245-HCB. 245-HCB-treatment elevated the hepatic concentration of cytochrome P450 and also the activities of 7-pentoxyresorufin O-depentylase (50-fold), aniline p-hydroxylase (2-fold) and 7-ethoxycoumarin O-deethylase (2-fold), a response typical of phenobarbital-type inducers. In the Western immunoblot of liver microsomes from 245-HCB treated rats, an increased amount of P450IIB1/2 was detected by a monoclonal antibody 2-66-3, which specifically detects phenobarbital inducible isoenzymes. The minimum molecular mass of the P450 isozyme induced was 52 kDa. After 236-HCB administration, a weak inducing effect was observed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02098033
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