Toxicity of mixtures of parathion, toxaphene and/or 2,4-D in mice.

The toxicity of the mixtures of parathion (PA), toxaphene (TOX) and/or 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in ICR male mice (21-24 g) by oral intubation, in corn oil, daily for up to 14 days. On Day 15, the exposure was discontinued, and animals were monitored for an additional period of 7 days for the possible reversibility of the toxicity. The body weight gain decreased with the mixtures, as well as with the individual agricultural chemicals (ACs), during the 14-day period. The cholinesterase (ChE) activity in the serum and brain was inhibited in the animals of the groups of PA (1-10 mg kg-1) and PA (5 mg kg-1)-containing mixtures. TOX (50-200 mg kg-1) caused initial inhibitory effects of 20-65% on the serum ChE (Day 1) before producing increases of 53-64% in the enzyme activity by Day 15, with little effects on the brain ChE levels. 2,4-D (50-200 mg kg-1) resulted in significantly elevated levels of the serum ChE, with substantial decreased in the brain ChE activity. The serum glutamic pyruvic transaminase level was up (38-630%) in TOX (50 mg kg-1), 2,4-D (50 mg kg-1) or their mixture group. No pathological changes at the light microscopic level in the brain and liver were noticed. TOX and TOX-containing mixtures significantly increased the liver/body weight ratio and decreased the pentobarbital (60 mg kg-1, i.p., in saline)-induced sleep.(ABSTRACT TRUNCATED AT 250 WORDS)