ABSTRACT
Over the past eight years, small doses of an organophosphorous insecticide known in Japan as Sumithion (fenitrothion) have been administered weekly to rehsus monkeys and beagles. In this report, the results obtained during the past three years are discussed.<BR>During the period, two monkeys and one hound died. Pathohistological examination revealed degeneration and disappearance-regeneration of liver tissues, edema of oculomotor muscle stomas, spinal cords and oculomotorius nerve fibers, and atrophy of limph nodes. These are considered the effects of the insecticide.<BR>The surviving animals did not develop any abnormal changes or signs associated with Sumithion-induced disorders. Weight loss was not observed. Routine blood tests were negative. However, serum chemical analyses conducted in the seventh year showed that there are statistically significant differences in GPT, LDH and cholinestrase activity among the animals.
