Table 1.
Effects of menadione on parathion levels and esterase activities in rat tissues36
| Treatment |
||
|---|---|---|
| Parathion | Parathion + menadione | |
| Parathion levels in tissue | ||
| Liver (µg/g tissue) | 1.9 ± 0.3 | 1.9 ± 0.5 |
| Brain (µg/g tissue) | 0.1 ± 0.05 | 0.9 ± 0.3 |
| Serum (µg/mL) | 0.4 ± 0.1 | 2.4 ± 0.3 |
| CES activity (% control) in tissue | ||
| Liver | 6.4 ± 0.5 | 15.3 ± 1.5 |
| Serum | 7.0 ± 1.8 | 18.0 ± 2.1 |
| ChE activity (% control) in brain | ||
| Forebrain | 7.3 ± 1.1 | 90.0 ± 3.6 |
| Hindbrain | 15.5 ± 1.3 | 86.8 ± 2.3 |
Rats were administered parathion (8 mg/kg, oral gavage) followed 20 min later by menadione (40 mg/kg, IP). Sixty minutes after parathion treatment, rats were sacrificed. Carboxylesterase (CES) and cholinesterase (ChE) activities were determined using p-nitrophenylvalerate and acetylthiocholine as the substrates, respectively.