Abstract

1. Heptachlor epoxide has been isolated from rats fed heptachlor. It is the identical isomer to the one isolated from the dog.

2. A method for the quantitative determination of heptachlor epoxide in biological tissue is described.

3. Tissue distribution studies indicate that heptachlor epoxide accumulates primarily in the fat of dogs and rats, other tissues containing relatively low levels, except the brain which had none. In the dog the liver appears to store levels somewhat higher than the other organs tested beside the fat.

4. In the dog at high levels of heptachlor administration, traces of heptachlor were found in the fat in addition to heptachlor epoxide.

5. Heptachlor epoxide accumulates rapidly in the fat of rats fed heptachlor at a level of 30 ppm. in the diet. Maximum concentration in the fat was reached in two to four weeks. Twelve weeks were required for complete disappearance from the fat after discontinuing heptachlor feeding.

6. Females accumulate approximately six times as much epoxide in the fat as do males.

7. The concentration of heptachlor epoxide in the fat appears to bear a relationship to the concentration of heptachlor in the diet. Measurable levels of storage occurred at all dietary levels above 0.1 ppm. in rats.

8. Heptachlor epoxide is more toxic intravenously to mice than the parent compound, heptachlor.