David J. Hoffman Barnett A. Rattner 1984 <p><span>The LD50 (95% confidence limits) of the organophosphorus insecticide acephate was estimated to be 351, 380, and 321 mg/kg (295–416, 280–516, and 266–388 mg/kg) for CD-1 laboratory mice (</span><i>Mus musculus</i><span>), white-footed mice (</span><i>Peromyscus leucopus noveboracensis</i><span>), and meadow voles (</span><i>Microtus pennsylvanicus</i><span>), respectively. In a second study, these species were provided mash containing 0, 25, 100, and 400 ppm acephate for five days. Brain and plasma cholinesterase activities were reduced in a dose-dependent manner to a similar extent in the three species (inhibition of brain acetyl-cholinesterase averaged for each species ranged from 13 to 22% at 25 ppm, 33 to 42% at 100 ppm, and 56 to 57% at 400 ppm). Mash intake, body or liver weight, plasma enzyme activities (alkaline phosphatase, alanine and aspartate aminotransferase), hepatic enzyme activities (aniline hydroxylase, 7-ethoxycoumarin O-deethylase, and glutathione S-transferase), and cytochrome content (P-450 and b</span>₅<span>) were not affected by acephate ingestion, although values differed among species. In a third experiment, mice and voles received 400 ppm acephate for 5 days followed by untreated food for up to 2 weeks. Mean inhibition of brain acetylcholin-esterase for the three species ranged from 47 to 58% on day 5, but by days 12 and 19, activity had recovered to 66 to 76% and 81 to 88% of concurrent control values. These findings indicate that CD-1 laboratory mice, white-footed mice, and meadow voles are equally sensitive to acephate when maintained under uniform laboratory conditions. Several factors (</span><i>e.g.</i><span>, behavior, food preference, habitat) could affect routes and degree of exposure in the field, thereby rendering some species of wild rodents ecologically more vulnerable to organophosphorus insecticides.</span></p> application/pdf 10.1007/BF01056263 en Springer Comparative toxicity of acephate in laboratory mice, white-footed mice, and meadow voles article