Carcinogenesis with the insecticide rotenone

Rotenone is an insecticide which has been used extensively for a long time, and is now widely used in the U.S.A. and other industrialized countries. Rotenone is used mainly as an agricultural insecticide, household garden insecticide and water plant pesticide. Through these uses, rotenone may now be reaching the human male and female in these countries in substantial amounts, carried by fresh or cooked vegetables, consumed fish and drinking water. A review of the existing published reports and unpublished official documents dealing with the capacity of rotenone to induce neoplastic, paraneoplastic and preneoplastic lesions in the rat is presented here. It is strongly suggested that rotenone is carcinogenic to the rat (at doses from 2 to 25 parts per million continuously in food, or from 0.8 to 2.5 mg/kg weight for 1 to 4 months by oral administration), above all, when the rats receive deficient diets, especially those poor in riboflavin. Rotenone carcinogenesis, among other things, seems to exhibit a peculiar dose response pattern, which could be explained by its possible hormonal mechanism of action. Further studies to assess definitively the role of rotenone as a possible environmental carcinogen are proposed as being highly necessary.