Abstract
Polychlorinated biphenyl (PCB) mixtures and individual chlorobiphenyl (CB) congeners have various endocrine-disrupting effects, but ultimate responses may be altered by concurrent effects on enzyme levels and enzyme activities. The toxicodynamics of estrogenic PCBs and metabolites have been studied in vitro, but nonlinear dose-response relationships in vivo suggest that tests must integrate toxicokinetic parameters to explain whole-animal responses. To determine if any such interactions occurred, relatively large doses were subdivided into different treatment regimens for immature female Sprague-Dawley rats. Aroclor 1242 was uterotropic when 120 mg/kg (total) was administered (intraperitoneally) in two, three or five doses. CB 47 (2,2',4,4'-tetraCB) and CB 153 (2,2',4,4',5,5'-hexaCB) increased absolute uterine weights at 30 mg/kg on days 20 and 21. Results at 25 days in rats that received zero, two, three or five doses between days 20 and 24 were much more variable due to changes in tissue responsiveness and/or toxicokinetic interactions. In rats receiving treatment for 5 days, pentoxyresorufin O-dealkylase (PROD) activity was inversely related to CB serum residues; in rats receiving CB 153 for 2 days, PROD activity was directly related to serum residues. It was not clear whether PROD activity was the cause of or a reflection of lower serum residues; however, nonplanar CBs are better substrates for PROD than are planar CBs, and the longer-term dosing may enhance metabolism and excretion, changing the biological effects observed.
Full text
PDF



Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Birnbaum L. S. Distribution and excretion of 2,3,6,2',3',6'- and 2,4,5,2',4',5'-hexachlorobiphenyl in senescent rats. Toxicol Appl Pharmacol. 1983 Sep 15;70(2):262–272. doi: 10.1016/0041-008x(83)90102-3. [DOI] [PubMed] [Google Scholar]
- Bitman J., Cecil H. C., Harris S. J. Biological effects of polychlorinated biphenyls in rats and quail. Environ Health Perspect. 1972 Apr;1:145–149. doi: 10.1289/ehp.7201145. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Colborn T., vom Saal F. S., Soto A. M. Developmental effects of endocrine-disrupting chemicals in wildlife and humans. Environ Health Perspect. 1993 Oct;101(5):378–384. doi: 10.1289/ehp.93101378. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ecobichon D. J., MacKenzie D. O. The uterotropic activity of commercial and isomerically-pure chlorobiphenyls in the rat. Res Commun Chem Pathol Pharmacol. 1974 Sep;9(1):85–95. [PubMed] [Google Scholar]
- Hansen L. G., Welborn M. E. Distribution, dilution and elimination of polychlorinated biphenyl analogs in growing swine. J Pharm Sci. 1977 Apr;66(4):497–501. doi: 10.1002/jps.2600660410. [DOI] [PubMed] [Google Scholar]
- Jansen H. T., Cooke P. S., Porcelli J., Liu T. C., Hansen L. G. Estrogenic and antiestrogenic actions of PCBs in the female rat: in vitro and in vivo studies. Reprod Toxicol. 1993 May-Jun;7(3):237–248. doi: 10.1016/0890-6238(93)90230-5. [DOI] [PubMed] [Google Scholar]
- Korach K. S., Sarver P., Chae K., McLachlan J. A., McKinney J. D. Estrogen receptor-binding activity of polychlorinated hydroxybiphenyls: conformationally restricted structural probes. Mol Pharmacol. 1988 Jan;33(1):120–126. [PubMed] [Google Scholar]
- Lund B. O., Bergman A., Brandt I. Decreased pulmonary drug metabolism in mice treated with the PCB metabolite 4-methylsulphonyl-2,2',5,5'-tetrachlorobiphenyl. Toxicol Lett. 1986 Sep;32(3):261–267. doi: 10.1016/0378-4274(86)90117-7. [DOI] [PubMed] [Google Scholar]
- Nelson J. A. Effects of dichlorodiphenyltrichloroethane (DDT) analogs and polychlorinated biphenyl (PCB) mixtures on 17beta-(3H)estradiol binding to rat uterine receptor. Biochem Pharmacol. 1974 Jan 15;23(2):447–451. doi: 10.1016/0006-2952(74)90436-5. [DOI] [PubMed] [Google Scholar]
- Safe S., Astroff B., Harris M., Zacharewski T., Dickerson R., Romkes M., Biegel L. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related compounds as antioestrogens: characterization and mechanism of action. Pharmacol Toxicol. 1991 Dec;69(6):400–409. doi: 10.1111/j.1600-0773.1991.tb01321.x. [DOI] [PubMed] [Google Scholar]
- Safe S. Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and related compounds: environmental and mechanistic considerations which support the development of toxic equivalency factors (TEFs). Crit Rev Toxicol. 1990;21(1):51–88. doi: 10.3109/10408449009089873. [DOI] [PubMed] [Google Scholar]
- Schmoldt A., Herzberg W., Benthe H. F. On the inhibition of microsomal drug metabolism by polychlorinated biphenyls (PCB) and related phenolic compounds. Chem Biol Interact. 1977 Feb;16(2):191–200. doi: 10.1016/0009-2797(77)90128-4. [DOI] [PubMed] [Google Scholar]