Lethality, hexobarbital narcosis and behavior in rats exposed to atrazine, bentazon or molinate.
Previous findings from our laboratory suggested a possible interaction of atrazine, bentazon and molinate with other environmental and/or occupational poisons. The aim of this research was to obtain further toxicological information by using phenobarbital-induced rats and to characterize the effects of these herbicides on the hepatic microsomal metabolism of xenobiotics. Acute experiments have shown that the LD50 is augmented by the barbiturate pretreatment when atrazine is used, remains unchanged in the case of bentazon, but is lowered when molinate is given. Recrystallized atrazine, in the absence of the wetting compounds, elicits the same acute toxicity found when animals are challenged with a commercial preparation. No significant sex-related differences have been observed. In long-term treatment with these toxicants, atrazine shortened the hexobarbital narcosis, but no effect was observed after administration of either bentazon or molinate. Further studies on hexobarbital sleeping time demonstrated that females are more susceptible than males to the narcotic effect of this compound. The induction-like effect of atrazine exposure has been confirmed, mainly in young animals. At the end of the sleeping time, the actual serum concentration of hexobarbital is practically the same, and is not related to the length of the sleeping time. The absence of behavioral alterations in the open field tests exclude possible neurological effects of the triazine herbicide. In conclusion, these data demonstrate that atrazine by itself induces the hepatic pharmacometabolic system, while its metabolites result less toxic than the parent compound. On the contrary, metabolic transformations render the toxic effects of bentazon more severe.
Ugazio
G
G
Dipartimento di Medicina e Oncologia Sperimentale, Sezione di Patologia Ambientale, Torino, Italy.
Bosio
A
A
Burdino
E
E
Ghigo
L
L
Nebbia
C
C
D000367:Age Factors; D000818:Animals; D001280:Atrazine / Q000378:metabolism / Q000633:toxicity*; D001381:Azepines / Q000633:toxicity*; D001581:Benzothiadiazines / Q000633:toxicity*; D005260:Female; D006540:Herbicides / Q000633:toxicity*; D006591:Hexobarbital / Q000378:metabolism / Q000494:pharmacology*; D007928:Lethal Dose 50; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D012737:Sex Factors; D012890:Sleep / Q000187:drug effects*; D013859:Thiocarbamates
D001381:Azepines; D001581:Benzothiadiazines; D006540:Herbicides; D013859:Thiocarbamates; C009821:molinate; D006591:Hexobarbital; D001280:Atrazine; C002003:bentazone