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.

[Occurrence of harmful pollutants in fattened pigs].

Fourteen fattened pigs (age of 240-250 days, live weight 110-120 kg) were examined on three farms (D., M. and T.

[Occurrence of chlorinated pesticides and polychlorinated biphenyls in the stalls and outdoor environment in pig-fattening farms].

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).