Acute, subchronic and chronic 2,4-dichlorophenoxyacetic acid (2,4-D) intoxication in rats.
The acute, subchronic and chronic toxicities of 2,4-dichlorophenoxyacetic acid (2,4-D) were studied ir rats. Animals were exposed acutely (600 mg/kg), subchronically (200 ppm for 30 d) and chronically (200 ppm for 180 d) to 2,4-D by the oral route. Clinical, laboratory and histopathological methods were used as indicators of toxicity. After acute exposure, the herbicide decreased locomotor activity and induced ataxia, sedation, muscular weakness (mainly of the hind quarters) and gasping for breath; increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (AP), amylase activities and creatinine levels; decreased total protein (TP) and glucose levels; and increased hematocrit values. Subchronic and chronic 2,4-D exposures did not induce overt clinical signs or symptoms of intoxication. However, subchronic herbicide exposure increased AST activity and albumin and hematocrit values, and chronic exposure increased AST, AP and LDH activities, decreased amylase and glucose levels, but did not change hematocrit values. Chromatographic analysis of the serum of chronically exposed rats showed the presence of the herbicide; the amount found (3.76 +/- 1.16 micrograms/ml) suggested the absence of 2,4-D accumulation within the body. Although macroscopic or histopathological lesions were not observed in acutely, subchronically or chronically 2,4-D exposed rats, the laboratory data obtained suggest tissue injuries after dosing, since the results are considered early indicators of primarily hepatic and muscle tissue damage.
Department of Pathology, School of Veterinary Medicine, University of Sao Paulo, Brazil.
C A
CA
Paulino
J L
JL
Guerra
G H
GH
Oliveira
J
J
Palermo-Neto
D015084:2,4-Dichlorophenoxyacetic Acid / Q000008:administration & dosage / Q000633:toxicity*; D000284:Administration, Oral; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000681:Amylases / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D001798:Blood Proteins / Q000187:drug effects; D003404:Creatinine / Q000097:blood; D006400:Hematocrit; D006540:Herbicides / Q000008:administration & dosage / Q000633:toxicity*; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000293:injuries; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000293:injuries; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D001798:Blood Proteins; D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid; D003404:Creatinine; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D000681:Amylases