BIOLOGICAL EFFECTS OF INHALED MAGNESIUM-SULFATE WHISKERS IN RATS

Male Wistar rats were exposed to two types of magnesium sulphate whisk ers by inhalation for six hours a day, five days a week, for four week s (sub-chronic study), or for one year (chronic study) to clarify the biological effects of the whiskers. There were few whiskers detected i n the rat lungs even at one day after the exposure, suggesting that th ey are dissolved and eliminated rapidly from the lungs. To measure the clearance rate of the whiskers from the lungs, an intratracheal insti llation was performed in golden hamsters. The half life of the whisker s in the lung was determined as 17.6 minutes by temporally measuring t he magnesium concentration up to 80 minutes after the instillation. A histopathological examination indicated a frequent occurrence of adeno ma and carcinoma in the year after chronic exposure, but it was not si gnificantly different between exposed and control rats.