Abstract
Rabbits were injected intratracheally manganese dioxide (400 mg/kg). Serum calcium, inorganic phosphates and alkaline phosphatase levels were determined at the interval of 60 days over a period of 240 days. Simultaneously histological studies were carried out in parathyroids, bones and kidneys. A significant decrease in the levels of serum alkaline phosphatase, inorganic phosphates and an increase in calcium was noted at 180 days. These biochemical alterations occured at a much earlier stage than the development of symptoms of manganese encephalopathy which are of great significance to detect early toxicity.
