Influence of Environmental Contamination on Cytochrome P-450 Mixed-Function Oxygenases in Fish: Implications for Recovery in the Wild Harbor Marsh

1978 ◽  
Vol 35 (5) ◽  
pp. 668-674 ◽  
Author(s):  
John J. Stegeman
Keyword(s):  
Environmental Contamination ◽  
Fundulus Heteroclitus ◽  
Oxygenase Activity ◽  
Marsh Site ◽  
In The Wild ◽  
Pyrene Hydroxylase ◽  
Catalytic Functions ◽  
Mixed Function Oxygenase ◽  
Cytochrome P 450 ◽  
Hepatic Cytochrome

Levels of hepatic cytochrome P-450 and the catalytic functions benzo[a]pyrene hydroxylase and aminopyrine demethylase were significantly greater in populations of mummichog, Fundulus heteroclitus, sampled from contaminated marshes than in those fish from nearby reference marshes. Aminopyrene demethylase, but not benzo[a]pyrene hydroxylase, was also elevated in fish from one of the reference marshes. The levels of cytochrome P-450 and benzo[a]pyrene hydroxylase were highest in fish from the Wild Harbor Marsh, site of the 1969 Florida spill. A correlation between size and benzo[a]pyrene hydroxylase activity was identified in some of the populations studied, although influence by this factor did not mask the population differences. The results are consistent with the hypothesis that elevated levels of mixed-function oxygenase activity in fish from Wild Harbor are the result of oil spilled 8 yr ago, and that recovery of this marsh is not yet complete. Key words: mixed-function oxygenases, benzo[a]pyrene hydroxylase, aminopyrine demethylase, cytochrome P-450, Fundulus heteroclitus, environmental contamination, oil spill recovery, petroleum

Temperature Influence on Basal Activity and Induction of Mixed Function Oxygenase Activity in Fundulus heteroclitus

1979 ◽  
Vol 36 (11) ◽  
pp. 1400-1405 ◽  
Author(s):  
John J. Stegeman
Keyword(s):  
Cytochrome C ◽  
Fundulus Heteroclitus ◽  
Reductase Activity ◽  
Control Fish ◽  
Cytochrome C Reductase ◽  
Nadph Cytochrome ◽  
Pyrene Hydroxylase ◽  
Mixed Function Oxygenase ◽  
Cytochrome P 450 ◽  
Nadph Cytochrome C Reductase

Treatment of Fundulus heteroclitus acclimated to 6.5 °C with benzo(a)pyrene did not elicit any change in the levels of hepatic microsomal NADH- or NADPH-cytochrome c reductase activity, nor in the levels of cytochrome P-450 or its catalytic activities. However, the same treatment offish at 16 5 °C resulted in a marked induction of benzo(a)pyrene hydroxylase and NADPH-cytochrome c reductase. Cytochrome P-450 content was also higher in the warm, treated fish and the Soret maximum of reduced, CO-treated microsomes was shifted to the violet. Levels of aminopyrine demethylase and NADH-cytochrome c reductase activities did not show a significant treatment effect. At neither temperature could treated and control fish be distinguished on the basis of in vitro inhibition of benzo(a)pyrene hydroxylase activity by 7,8-benzoflavone. Levels of NADPH-cytochrome c reductase and benzo(a)pyrene hydroxylase activities were greater in control Fundulus acclimated to 6.5 °C than to 16.5 °C, when normalized to microsomal protein, but not when based on body weight. The results indicate that habitat temperature alone may not affect the capacity for initial hydrocarbon metabolism in fish, but that it can strongly influence the induction of cytochrome P-450. Key words: temperature, cytochrome P-450, hydrocarbon metabolism, mixed-function oxygenase, Fundulus heteroclitus

Sex differences in hepatic cytochrome P-450 monooxygenase activities in rainbow trout during an annual reproductive cycle

1990 ◽  
Vol 124 (2) ◽  
pp. 207-213 ◽  
Author(s):  
L. Förlin ◽  
C. Haux
Keyword(s):  
Rainbow Trout ◽  
Reproductive Cycle ◽  
Annual Reproductive Cycle ◽  
Aryl Hydrocarbon Hydroxylase ◽  
Aryl Hydrocarbon ◽  
Natural Photoperiod ◽  
Pyrene Hydroxylase ◽  
Cytochrome P 450 ◽  
Isoenzyme Patterns ◽  
Hepatic Cytochrome

ABSTRACT Hepatic microsomal cytochrome P-450 monooxygenase activities were investigated in rainbow trout during an annual reproductive cycle. The fish were kept in tanks supplied with fresh water at a constant temperature of 10 °C. The daily light and darkness cycle was adjusted to follow the natural photoperiod. Sampling was performed once every month for 1 year. Higher benzo(a)pyrene-hydroxylase (or aryl hydrocarbon hydroxylase; AHH), ethoxycoumarin-O-deethylase (ECOD) and ethylmorphine-N-demethylase (END) activities and cytochrome P-450 content were found during the late stage of sexual development in rainbow trout. When monooxygenase activities were expressed on a per cytochrome P-450 basis, sex-dependent differences were observed only for AHH and ECOD activities. It was thus found that sex-dependent variations of END were closely correlated with the total amount of cytochrome P-450. The results indicate that differences exist in hepatic cytochrome P-450 isoenzyme patterns between the sexes in rainbow trout. The similarity of the annual pattern of plasma levels of oestradiol and testosterone to that of sex-dependent differences in the cytochrome P-450 monooxygenases support the contention that sex steroids play a role in regulating the cytochrome P-450 system. Journal of Endocrinology (1990) 124, 207–213

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