The production of hemangioendothelialsarcoma in rats by feeding 5-acetamido-3-(5-nitro-2-furyl)-6H-1,2,4-oxadiazine.

Thirty-five female Sprague-Dawley weanling rats were fed 5-acetamido-3-(5-nitro-2-furyl)-6H-l ,2,4-oxadiazine for 37 weeks. All 32 rats surviving 28 weeks or more developed hemangioendothelialsarcomas at one or more sites. These unusual tumors were located in the livers of 31 rats, in the mesentery of 30 rats, and in the lungs of 5 rats. Nine rats developed alveolar carcinomas, and 1 rat developed a benign fibroadenoma of the mammary gland. The distribution of tumors observed following the administration of this nitrofuran derivative was surprisingly different from that observed after feeding ./V-[4-{5-nitro-2-furyl)-2-thiazolyl] formamide, a potent urinary bladder carcinogen for the rat.