Effects of Oral and Intrasplenic Administration of Cortisone. ∗

Abstract

Summary

(1) Thymic weight loss in 14 hours offers an accurate quantitative endpoint by means of which to measure the action of cortisone when administered by different routes. (2) Under conditions of our experiment, cortisone was much more effective when administered by subcutaneous route as compared with the oral or intrasplenic route. The subcutaneous:oral ratio is about 1:15. (3) Sensitivity of adrenalectomized mice to the thymolytic action of cortisone did not differ from that of intact animals. (4) Administration of small doses of cortisone, which caused thymic involution when given by subcutaneous route, failed to do so when given by intrasplenic or oral route. This suggests that inactivation by the liver, previously found in in vitro experiments, also plays a role in vivo. If the dose administered through the portal routes is large, sufficient amounts escape inactivation to produce a maximal effect upon the thymus.