The mean levels of cytochrome b5 measured in fish from BK, OK, and RR and in fish 

 injected with BNF were similar (Table 30). This measure likely represents the denatured, 

 inactive form of cytochrome P-450. The origin of this degradation is not certain, but could 

 have resulted from the procedures involved in freezing the liver tissue on dry ice. The 

 levels of cytochrome P-420 also were fairly similar among sites. A major pathway of 

 estradiol metabolism in fish is apparently through 2-hydroxylation. Mean measures of 

 estradiol 2-hydroxylase in BK control and BNF-injected fish were essentially identical when 

 expressed as nmol/min/mg protein, but considerably lower in BNF-injected fish when 

 expressed as a function of total native P-450 content (Table 30). Expressed as nmol/min/nmol 

 native P-450, the mean estradiol 2-hydroxylase activity was lowest in the BK and OK fish. 

 The fish used in the experimental evaluation were immature females. Also, all of the SP 

 fish that were analyzed were immature females. The comparable mean values for immature 

 females from the BK, OK, VJ, SP, and RR sites were: 0.126 ± 0.037, 0.213 + 0.122, 0.246 ± 

 0.080, 0.299 ± 0.066, and 0.344 ± 0.148 nmol/min/nmol native P-450, respectively. Therefore, 

 these mean values indicated that estradiol hydroxylation was lower in the fish from the 

 two sites (OK and BK) where mean cytochrome P-450 induction was highest. They were 

 highest in the sites (SP and RR) where induction was lowest. 



Results of analyses of the few fish caught in the January-February collections are 

 summarized in Table 31. No conclusions can be drawn from the data because of the small 

 sample size. Total cytochrome P-450 activity was very high in SC fish, but a large 

 proportion of that activity was represented by cytochrome P-420, the putative inactive form. 



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