Effect of cyclophosphamide on serum ceruloplasmin oxidase activity in sarcoma bearing rats

High levels of serum ceruloplasmin oxidase activity were detected in U strain isogenic male rats bearing a syngeneic sarcoma in all phases of tumoral evolution. Normal levels of ceruloplasmin were only observed after a single i.p. dose of cyclophosphamide (100 mg/kg). However subsequent weekly administration of the drug did not prevent the return of hyperceruloplasminemia in the tumor hosts. Normal rats treated similarly with cyclophosphamide presented a fall in the enzyme activity after the 1st dose.