Hepatic microsomes prepared from 10 fish species from Bermuda were studied to establish features of cytochrome P450 (CYP) systems in tropical marine fish. The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 and 0.25 nmol/mg. Ethoxycoumarin O-deethylase (ECOD) and aminopyrine N-demethylase (APND) rates in these 7 species ...

Relative potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and 2,3,7,8-tetrachlorodibenzofuran (TCDF) were determined in vitro in primary hepatocyte cultures of chicken (Gallus gallus), ring-necked pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) embryos. Concentration-dependent effects on ethoxyresorufin O-deethylase (EROD...

Ethoxyresorufin O-deethylase (EROD) activity was measured in primary cultures of ring-necked pheasant (Phasianuscolchicus) and Japanese quail (Coturnix japonica) embryonic hepatocytes exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) for 12, 24, 36 and 48 h. In ring-necked pheasant hepatocytes there was a ...

Cytochrome P450 1A1 (CYP1A1) and 1B1 (CYP1B1) are phase I enzymes, the expression of which can be affected by many environmental compounds, including dioxins and dioxin-like compounds. Because CYP1A1 and CYP1B1 expression can easily be determined in peripheral blood lymphocytes, it is often suggested as biomarker of exposure to these compounds. In this study we investigated the interindividual ...

Some polychlorinated biphenyl (PCB) congeners are CYP1A1 inducers, and induction of this enzyme in the placenta has been linked to adverse effects on fetal development. The objective of this study was to determine if the body burden of PCBs is related to placental CYP1A1 activity in Inuit women from Nunavik (northern Québec), a population highly exposed to organochlorines. Placenta and cord blo...

The objective of this study was to determine whether recombinant human cytochrome P450 1B1 (rhCYP1B1) metabolizes the anticancer agent docetaxel (Taxotere) in vitro. First, the catalytic activities of Supersomes-expressed rhCYP1B1 toward 17beta-estradiol and of rhCYP3A4 toward docetaxel in our conditions were determined. Second, [(14)C]docetaxel at 0.1 and 1 microM was incubated with rhCYP1B1 i...

Oceans function as a sink for organochlorine compounds (OCs) such as PCBs and DDTs. Deep-sea fish bioaccumulate OCs to levels 10 to 100 times higher than shallow-water species. OCs induce the cytochrome P450 (CYP) system, the activity of which may increase reactive oxygen species (ROS) production in liver cells. However, the susceptibility of fish to the oxidative stress likely caused by OCs re...

Although there have been numerous studies involving fish, birds, and mammals, little is known about the response of the cytochrome P4501A system of snakes to halogenated aromatic hydrocarbons (HAHs). The present study describes the induction of ethoxyresorufin-O-deethylase (EROD) in primary hepatocytes of the African brown house snake (Lamprophis fuliginosus). Hepatocytes were exposed in multiw...

The uptake and subcellular partitioning of benzo[a]pyrene (BaP) were examined in a rat-liver cell line (Clone 9) using confocal and multiphoton microscopy. Following a 16-h treatment, intracellular accumulation of BaP increased with increasing concentration, and cytoplasmic BaP fluorescence reached saturation at 10 microM. Analysis of the kinetics of BaP uptake at this concentration indicated t...

Biochemical markers, specifically enzymes of the first phase of xenobiotic transformation - cytochrome P450 and ethoxyresorufin-O-deethylase (EROD) - were used to determine the quantities of persistent organic pollutants (POPs) in fish muscle (PCB, HCB, HCH, OCS, DDT). Eight rivers were monitored (Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohře and Bílina; and the River Blanice was used as a c...