Toxicity of endosulfan: Distribution of α- and ß-isomers of racemic endosulfan following oral administration in rats

Endosulfan was administered orally (2.5 and 7.5 mg/kg) daily to male rats for a period of 60 days. The distribution pattern of α and ß-isomers was studied using a gas-liquid chromatography equipped with an electron capture detector. There was a significant increase in liver and lung weights. The testes weight was slightly decreased. No significant change in weights of other tissues was observed. At both dose levels, the concentration of α-isomer was highest in kidney (574 and 1655 ng/g, respectively), followed by lung, ventral prostate, spleen, testes and brain. In the seminal vesicle, epididymis, heart and liver, the concentration of ß-isomer was higher than the α-isomer. The results of the study indicated a differential ability to accumulate the two isomers of endosulfan which may help to explain the difference in the toxic potential of the α- and ß-isomers.