MODELLING SYNERGISTIC EFFECTS OF TWO TOXIC AGENTS IN THE HONEYBEE

Publisher Website
Google Scholar
Abstract
In previous experiments, a synergistic lethal effect on the honeybee has been demonstrated with two toxic agents: deltamethrin and prochloraz. The toxic agents were applied simultaneously or sequentially. Deltamethrin is metabolized by esterase and by cytochrome P-450-dependent monooxygenase. Prochloraz is a potent competitive inhibitor of cytochrome P-450. An attractive hypothesis explaining this synergic toxicity is that the persistence of deltamethrin is due to inhibition of the oxidative metabolism of deltamethrin by prochloraz. We tested this hypothesis using a mathematical model. A compartmental model in continuous time was constructed to represent this synergy by analyzing the degradation of toxic agents. This pharmacokinetic model was based on differential equations, using numerical resolution and Runge-Kutta’s integration method. When applied to a mixture of toxic agents, this model implies that the cumulative mortality of both compounds might be delayed compared to the mortality from treatment with toxic agents used separately. The hypothesis of metabolic synergy is compatible with experimental data only if the half-life of deltamethrin is short. The data from the model and the experimental data, diverged when deltamethrin was administered before prochloraz, which suggests that the phenomenon is more complex than expected.
Keywords

This publication has 0 references indexed in Scilit: