Table 3.
Carboxylesterase activity in liver cytosol from pesticide-exposed juvenile Chinook salmona
| Pesticide | Substrate | Concentration (μg/l)b | Average ± S.D.c | Ranged |
|---|---|---|---|---|
| Controle | PNPAf | 0 | 85.9 ± 22.0 | 2.2 |
| Acetateg | 0 | 20.8 ± 7.6 | 2.4 | |
| Butyrateh | 0 | 4.5 ± 1.0 | 1.9 | |
| Chlorpyrifos | PNPA | Solventi | 66.4 ± 11.0** | 1.7 |
| 1.2 | 29.4 ± 6.3* | 1.8 | ||
| 7.3 | 13.7 ± 1.2* | 1.3 | ||
| Acetate | Solvent | 11.6 ± 3.3** | 3.0 | |
| 1.2 | 13.4 ± 4.3 | 2.9 | ||
| 7.3 | 5.6 ± 1.7* | 2.4 | ||
| Butyrate | Solvent | 3.1 ± 0.3** | 1.4 | |
| 1.2 | 2.6 ± 0.9 | 3.9 | ||
| 7.3 | 1.4 ± 0.1* | 1.3 | ||
| Esfenvalerate | PNPA | Solvent | 73.1 ± 26.2 | 2.9 |
| 0.01 | 56.8 ± 11.4 | 1.8 | ||
| 0.1 | 63.7 ± 10.7 | 1.6 | ||
| Acetate | Solvent | 17.6 ± 8.0 | 3.3 | |
| 0.01 | 11.4 ± 3.9† | 3.0 | ||
| 0.1 | 13.5 ± 2.6 | 1.8 | ||
| Butyrate | Solvent | 4.0 ± 1.3 | 2.3 | |
| 0.01 | 3.0 ± 0.9 | 3.1 | ||
| 0.1 | 3.2 ± 0.4 | 1.5 |
Juvenile Chinook salmon were exposed to the indicated concentration of pesticide for 96 h as described in Section 2.
Esfenvalerate concentrations are nominal values and chlorpyrifos concentrations are measured.
Activity values are in units of nmol/min/mg and are the average ± the standard deviation (S.D.) for 10 fish (n = 10), except for the 7.3 g/l chlorpyrifos exposure (n = 8).
Range values are given as the fold difference in activity between the lowest and highest individuals.
Control fish were not exposed to either pesticides or vehicle and did not go through the experimental testing regimen.
Carboxylesterase activity assays were performed with the substrate p-nitrophenyl acetate (PNPA).
Carboxylesterase activity assays were performed with the substrate -cyano(6-methoxy-2-naphthyl)methyl acetate (acetate).
Carboxylesterase activity assays were performed with the substrate -cyano(6-methoxy-2-naphthyl)methyl butyrate (butyrate).
Solvent fish were exposed to the highest concentration of vehicle (0.005% MeOH) and went through the full 96 h testing regimen.
Statistically different from the solvent-exposed salmon (P < 0.001).
The solvent-exposed (MeOH vehicle) salmon were statistically different from the controls (P < 0.01).
The value is statistically different from the solvent-exposed salmon (P < 0.05).