Effects of Polychlorinated Biphenyl Mixtures and Three Specific Congeners on Growth and Circulating Growth-Related Hormones

Polychlorinated biphenyl effects on avian hepatic enzyme induction and thyroid function

“…At high doses, Aroclors 1254 and 1242 have been shown to decrease plasma T 4 concentrations in chicken embryos (Gould et al, 1999), but Aroclor 1254 had no effect on T 4 in another study on chicken embryos (Gould et al, 1997). At low doses, Aroclor 1242 significantly increased plasma T 4 concentrations in chicken embryos (Gould et al, 1997), and an organochlorine mixture that included PCBs also increased plasma T 4 concentrations in adult ring doves (Streptopelia risoria; McArthur et al, 1983). Aroclors 1254 (Gould et al, 1997) and 1242 (at high doses only; Gould et al, 1997;Gould et al, 1999) had no effect on circulating T 3 concentrations, but they caused decreased femur lengths in chicken embryos.…”

“…At low doses, Aroclor 1242 significantly increased plasma T 4 concentrations in chicken embryos (Gould et al, 1997), and an organochlorine mixture that included PCBs also increased plasma T 4 concentrations in adult ring doves (Streptopelia risoria; McArthur et al, 1983). Aroclors 1254 (Gould et al, 1997) and 1242 (at high doses only; Gould et al, 1997;Gould et al, 1999) had no effect on circulating T 3 concentrations, but they caused decreased femur lengths in chicken embryos. However, Gould et al (1999) found that Aroclor 1254 had no effect on femur length in chicken embryos, and the same authors (1997) found that low doses of Aroclor 1242 actually increased femur lengths in chicken embryos.…”

“…In addition, femur lengths are sometimes longer and sometimes shorter compared to controls in response to PCB exposure. At high doses, Aroclors 1254 and 1242 have been shown to decrease plasma T 4 concentrations in chicken embryos (Gould et al, 1999), but Aroclor 1254 had no effect on T 4 in another study on chicken embryos (Gould et al, 1997). At low doses, Aroclor 1242 significantly increased plasma T 4 concentrations in chicken embryos (Gould et al, 1997), and an organochlorine mixture that included PCBs also increased plasma T 4 concentrations in adult ring doves (Streptopelia risoria; McArthur et al, 1983).…”

“…In one study, it was shown that Aroclor 1242 and Aroclor 1254 decreased circulating T 4 concentrations after 21 days in chicken embryos (Gould et al, 1999). In another study, Aroclor 1254 had no effect on circulating T 4 concentrations after 17 days and Aroclor 1242 increased circulating T 4 concentrations after 17 days in chicken embryos (Gould et al, 1997). Circulating T 4 concentrations were not altered in chicken embryos exposed to PCBs 77 and 126 or in common tern chicks exposed to environmental PCBs in the field (McCleary, 2001;Murk et al, 1994).…”

PCB exposure and regeneration in crinoids (Echinodermata)

“…Exposure to PCBs has been clearly linked to developmental/reproductive toxicity in humans, primates, rodents, mink, fish, and other wildlife species (Golub et al 1991, Gould et al 1997. As PCBs and many other EDs are only slowly metabolized, they tend to be persistent in organisms and can have delayed effects.…”