The level of ceruloplasmin in plasma was measured as polyphenol oxidase activity in following groups of rats: 1. controls; 2. adrenalectomized; 3. shamadrenalectomized; 4. formalin arthritis; 5. ACTH treated (25 micrograms ACTH daily for 5 days); 6. adrenalectomized and ACTH treated (as in a