EXPERIMENTAL STUDIES ON TUMORS OF THE URINARY SYSTEM OF RATS INDUCED BY CHEMICAL CARCINOGENS

Tumors in rats were induced in the urinary system of rats with basic lead acetate (BLA), N-nitrosodimethylamine (DMN), N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), N-nitrosodibutylamine (DBN), 3-methylcholanthrene (3-MC) and 4-nitroquinollne 1-oxide (4NQO). These kidney, ureter and urinary bladder tumors were studied by histopatho-logy, histochemistry, autoradiography and electron microscopy. The tumors of the kidney were classified into the following 4 types; renal cell tumors, embryonal cell tumors, transitional cell tumors and hemangioendotheliomas. However, the tumors of all other regions were of one type, transitional cell tumors. Studies by light and electron microscopy and autoradiography and histochemlcal studies on the histogenesis of tumors of the urinary system in rats showed that renal cell tumors may originate from the renal tubular epithelium and from a part of the metanephrogenic tissue, embryonal cell tumors originate from metanephrogenic tissue and hemangioendotheliomas may originate from blood capillaries. Transitional cell tumors of the kidney, renal pelvis, ureter and bladder originate from transitional epithelium.