Effects of X-Irradiation and Adrenalectomy on Phagocytic Activity

Summary

1. 1. Following intravenous injection of Thorotrast into normal mice about 50% of the ThO₂ is taken up by the liver and 17% by the spleen. While the liver is about 10 times as large as the spleen and shows a greater total uptake of ThO₂, the ThO₂ uptake of splenic tissue per unit dry weight is almost 4 times that of hepatic tissue.

2. 2. The splenic uptake of ThO₂ in mice is linearly related to the amount of Thorotrast injected for doses up to 0.15 ml per mouse. With this dose each spleen contains about 6 mg of ThO₂ which makes up 15% of the dry weight of the organ. With doses above 0.15 ml the phagocytic cells of the spleen tend to become saturated, while with smaller doses the ability of the cells to take up additional ThO₂ does not appear to be influenced by the ThO₂ already ingested.

3. 3. X-irradiation (350 r) caused a great reduction in splenic weight but did not influence the 72 hour splenic or hepatic uptake of ThO₂ in mice. Doses from 100 r to 600 r were also without effect on the splenic uptake of ThO₂. After intraperitoneal injection with Micrococcus pyogenes var. aureus, leukocytes from the peritoneal cavities of irradiated mice (350 r) contained more bacteria than leukocytes from normal animals.

4. 4. Adrenalectomy caused a reduction in the phagocytic activity of mouse leukocytes which was marked at two days after adrenalectomy. By the sixth day after adrenalectomy however, the control and adrenalectomized groups were not significantly different in this respect. No change in splenic or hepatic uptake of ThO₂ was noted to follow adrenalectomy in mice. In rats, however, adrenalectomy caused a threefold reduction in the 24 hour splenic uptake of ThO₂.