Carcinogenicity of nickel subsulfide in Fischer rats and Syrian hamsters after administration by various routes.

In an endeavor to expand the variety of experimental models for study of nickel carcinogenesis, nickel subsulfide (Ni3S2) was administered to rodents by five previously untested routes. In two groups of Syrian hamsters, Ni3S2 induced multiple sarcomas at the sites of single im injections (5 or 10 mg of Ni3S2). In contrast, Ni3S2 did not induce any malignant tumors of the cheek pouches, oral cavity or gastrointestinal tract, despite multiple local applications to the cheek pouches of several groups of hamsters in total dosages as large as 1.1 g of Ni3S2. In a group of Fischer rats, single intratesticular injections of Ni3S2 (10 mg) induced many testicular sarcomas. In contrast, no malignant tumors developed in two groups of rats that received single injections into the submaxillary gland (2.5 mg of Ni3S2) or into the liver (5 mg of Ni3S2 via the portal venous system).