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Morphological studies of rat brain tumors induced by N-nitrosomethylurea.

✓ Experimental glial tumors were induced by weekly intravenous injections of N-nitrosomethylurea (NNMU) in rats. The tumors included low- and high-grade gliomas of the astrocytic series and mixed gliomas. The histology of the tumors did not vary significantly with serial passage through tissue culture, subcutaneous implantation, or freezing. These neoplasms provide reliable animal models of brain tumors common to man.