[Relevance of enzyme histochemistry of rat thyroid gland]

High doses of aniline analgesics produced increased lipofuscin accumulation in rats thyroid glands after 18 week's treatment. To assess the significance of this change histochemical, biochemical and functional tests have been performed. Increased benzidineperoxidase, decreased acid phosphatase and unchanged leucyl-beta-naphtylamidase activities have been found histochemically and partly confirmed by biochemical methods. 131I-uptake was unchanged and PBI-levels decreased. The selection of appropriate histochemical methods in combination with additional techniques is stressed.