Birgelen, APJM, KM Fase, J van der Kolk, H Poiger, A Brouwer, W Seinen
and M van den Berg. 1996. Synergistic effect of 2,2',4,4',5,5'-Hexachlorobiphenyl
and 2,3,7,8-Tetrachlorodibenzo-p-Dioxin on hepatic porphyrin
levels in the rat. Environmental
Health Perspectives 104:550-557.
Birgelen et al. report dramatic synergistic interaction between
a PCB congener, PCB 153, and dioxin.
studied the impact of several PCB congeners and dioxin on hepatic
porphyrin accumulation in rats. Hepatic
porphyrin accumulation has been observed in people following a hexachlorobenzene
poisoning in SE Turkey in the late 1960s, in industrial workers
producing certain herbicides, in the aftermath of the Seveso, Italy,
dioxin accident and in the Taiwanese Yu-Cheng PCB poisoning incident.
It has also been observed under field conditions (Herring gulls
in the Great Lakes) and laboratory experiments following exposure
to dioxin and related compounds. van Birgelen et al. studied
the effect of PCBs and dioxins on hepatic porphyrin accumulation
in rats in a lab diet experiment. They found a dose-dependent increase
in hepatic porphyrin accumulation after administration of the contaminants:
"this study clearly shows that porphyrins accumulate in the liver
after subchronic treatment with TCDD (dioxin), PCB 126, or PCB 156
PCB 153 by itself caused no increase in accumulation. Maximum increases
for dioxin alone were about twice control levels. But combining
PCB 153 and dioxin caused increases 800 times above control levels.