Effects of chronic exposure to PCBs on cytochrome P450 systems and steroidogenesis in liver and testis of bulls (Bos taurus).

Effects of chronic exposure to PCBs on the microsomal cytochrome P450 (CYP) enzymes in liver and testis of bulls (Bos taurus) were determined by comparing the constitutive and PCB-induced alkoxyresorufin O-dealkylase and testosterone hydroxylase activities. Specific inductions of the prevailing hepatic ethoxyresorufin O-deethylation and 6 beta-hydroxylation of testosterone are suggestive of the induction of CYP1A1 and CYP3A-like enzymes by PCBs. A high level of PCB-inducible androstenedione formation was also found. The hepatic CYP2B activities (i.e. pentoxyresorufin O-depentylase and testosterone 16 beta-hydroxylase) and CYP2C11-like testosterone 2 alpha-hydroxylase were increased only weakly. The testicular microsomal CYP activities were non-specifically reduced by the PCB exposure, except for the androstenedione formation and 16 beta-hydroxylation of testosterone. The inhibition of the activity of mitochondrial CYP11A, as the rate-limiting enzyme of steroidogenesis measured with resorufin 3 beta-hydroxy-22,23-bisnor-5-cholenyl ether as the fluorogenic substrate, exceeded 50% in testes of the PCB-contaminated bulls. The latter activity as well as the hepatic testosterone 6 beta-hydroxylation and hepatic and testicular androstenedione formation may significantly contribute to the decrease in testosterone levels after the PCB intake.

[Occurrence of harmful pollutants in fattened pigs]. / Zhodnocení výskytu rizikových polutantu u výkrmových prasat.

Fourteen fattened pigs (age of 240-250 days, live weight 110-120 kg) were examined on three farms (D., M. and T.) in Hodonin district in 1994 for the content of some harmful pollutants (mercury, cadmium, lead, lindane, DDT sum, DDT isomers, lower and higher chlorinated biphenyls, PCB congeners) in the muscle, liver, kidneys and subcutaneous fat. Maximum allowable quantities (MAQ) of extraneous matters were slightly exceeded in mercury only, in 5 samples of the muscle (0.012-0.022 mg/kg). In comparison with the average contents of extraneous matters in pigs in the Czech Republic in 1994, higher concentrations of mercury (0.009 mg/kg), lead (0.124 mg/kg), lindane (0.060 mg/kg fat) and DDT sum (0.083 mg/kg) were observed in the muscle of pigs from Hodonín district. The liver of the pigs contained the highest average concentrations of lead (0.141 mg/kg), lindane (0.280 mg/kg fat), DDT sum (0.323 mg/kg fat), p,p'-DDE (0.106 mg/kg fat), p,p'-DDT (0.057 mg/kg fat). PCB-Delor 103 (0.415 mg/kg fat), PCB-Delor 106 (0.561 mg/kg fat) and PCB 118 congener (0.029 mg/kg fat). The highest average values of mercury (0.014 mg/kg) and cadmium (0.147 mg/kg) were determined in the kidneys of pigs. The ratio of lower-chlorinated biphenyls (Delor 103) to higher-chlorinated biphenyls (Delor 106) was approximately 1 : 3 in the muscle, 1 : 1 in the liver and 1 : 2 in subcutaneous fat. The per cent share of three PCB congeners, 101, 138 and 153, was highest in the muscle, liver and subcutaneous fat of pigs. The pigs from Hodonín district exhibited in 1994 the greater load of mercury, lead, lindane and DDT than in other regions of the Czech Republic, but these values did not mostly exceed the hygienic limits in force. It is desirable to observe the spectrum of indicator PCB congeners for objective evaluation of PCB load in pigs, as they indicate the contamination level with lower- and higher-chlorinated biphenyls (Delor 103 to Delor 106). Greater attention should be paid to the congener PCB 118, which is the most toxic out of the indicator congeners concerned.

[Occurrence of chlorinated pesticides and polychlorinated biphenyls in the stalls and outdoor environment in pig-fattening farms]. / Výskyt chlorovaných pesticidu a polychlorovaných bifenylu ve stáajovém a mimostájovém prostredí farem pro výkrm prasat.

Contents of some pesticides (lindane, DDT sum, o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, o,p'-DDT, p,p'-DDT) and polychlorinated biphenyls (Delor 103, Delor 106, PCB congeners: 28, 52, 101, 118, 138, 153, 180) were investigated on three farms of fattened pigs (D., M. and T) in Hodonín district in 1994, as occurring in feed mixtures (n= 15), drinking water (n = 10), stable sedimented dust (n = 14), slurry (n = 10) and pavement dust (n = 5). Maximum permissible contents (MPC) of extraneous matters in feed mixtures were exceeded in lindane (two samples) and polychlorinated biphenyls (PCB). MPC of extraneous matters were not exceeded in drinking waters in any of the samples examined. Feed mixtures were found to have the highest average lindane content (0.054 mg/kg) and PCB sum (0.24 mg/kg); the ratio of lower chlorinated biphenyls (Delor 103) to higher chlorinated biphenyls (Delor 106) was 12:1; out of the PCB congeners, the highest amounts were determined for congeners 28 (0.067 mg/kg) and 52 (0.022 mg/kg); among the DDT isomers, isomer p,p'-DDT was prevailing (0.008 mg/kg). Drinking water had the 1:1 ratio of lower chlorinated to higher chlorinated biphenyls; out of the PCB congeners, the highest amounts were found out for congeners 28 (2.574 ng/l) and 101 (2.066 ng/l); among the DDT isomers, isomer p,p'-DDE was prevailing (1.887 ng/l). Stable dust was found to have the highest average level of DDT sum (0.026 mg/kg); the ratio of lower chlorinated to higher chlorinated biphenyls was 1:7; out of the PCB congeners, the highest amounts were determined for congeners 138 (0.036 mg/kg) and 153 (0.030 mg/kg); among the DDT isomers, isomer p,p'-DDE was prevailing (0.012 mg/kg). Slurry showed the 1:6 ratio of lower chlorinated to higher chlorinated biphenyls; out of the PCB congeners, the highest amounts were found out for congeners 138 (0.016 mg/kg dry matter) and 153 (0.014 mg/kg dry matter); among the DDT isomers, isomer p,p'-DDT was prevailing (0.005 mg/kg dry matter). Pavement dust had the 1:5 ratio of lower chlorinated to higher chlorinated biphenyls; out of the PCB congeners, the highest amounts were found out for congeners 138 (0.016 mg/kg) and 153 (0.012 mg/kg); among the DDT isomers, isomer p,p'-DDE was prevailing (0.005 mg/kg). Examination of feed mixtures and drinking waters will provide basic data on pollutant inputs to the stable environment. Stable sedimented dust is considered as an outstanding indicator of pollutant contamination of stable environment, regardless whether it comes from feed or other sources. Slurry examination will provide additional information on the total pollutant load of pig farms, informing us about outputs of extraneous matters residues from pig farms. Pavement dust examination indicates the level of pollutant load of outside stable environment as the pollutants can occasionally penetrate to the internal stable environment.