Significance of phosphorylation in organophosphate-mediated β-glucuronidase release from the rat liver

The elevation of rat blood β-glucuronidase caused in vivo by O,O-dialkyl O-phenyl phosphates and phosphorothioates correlated well with the electron-withdrawing tendency (σ^?) of leaving group substituents indicating the importance of a phosphorylation mechanism in the enzyme release. Hydrophobic bonding of these compounds may facilitate the phosphorylation since hydrophobicity (π) of substituents also correlated with the enzyme release. SKF 525-A decreased the elevation of β-glucuronidase by parathion through the suppression of paraoxon production. Pretreatment of rats with phenobarbital or DDE resulted in lower and delayed enzyme release caused by parathion.