A Morphometric Study of Rat and Hamster Lung Following Inhalation of 239 PuO 2

Abstract
Wistar rats and Syrian Golden hamsters inhaled 239PuO2 at doses near those for maximum lung tumor response in rats. Mean (.+-. SD) lung doses were 600 .+-. 290 rad for rats and 910 .+-. 840 rad for hamsters surviving from 120 to 350 days. Morphometric analyses were performed on light and electron micrographs of lung. Inhaled 239PuO2 had little effect on the overall structure or composition of lung at times up to 350 days after exposure. A number of species differences were noted. Different tissue responses of the lung parenchyma could not explain differences in lung tumor formation between rats and hamsters following inhalation of 239PuO2.