hibernate, such as white-footed mice, Peromyscus leucophus (Sanders and 

 Kirkpatrick 1977), and raccoons, Procyon lotor (Montz et al. 1982). The 

 implications of this are not clear, and additional research is needed. Other 

 systemic effects of PCBs that occur in a wide variety of animal species 

 include hepatic disorders distinguished by altered porphyrin metabolism, 

 increased thyroxin metabolism and ultrastructural changes in the thyroid, 

 inhibition of ATPases, interference with oxidative phosphorylation, 

 alterations in steroid hormone activities, immunosuppressive effects, and 

 altered vitamin A metabolism (EPA 1980; Safe 1984). 



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