HISTO- AND BIOCHEMICAL STUDIES ON DEHYDROGENASES IN TUMORIGENESIS IN RAT ZYMBAL GLANDS INDUCED WITH DMBA AND DAS

SOTOKICHI MORII, TADAMI KUMAZAWA, TAKEO KUSUMOTO, HISATOSHI HARADA, AIRO TSUBURA, NOBUAKI SHIKATA
1979 Acta Histochemica et Cytochemica  
Wistar SLC male rats were injected with 25 mg/Kg of 7,12-Dimethylbenz(a)anthracene intravenously twice at 51 and 66 days of age, and also fed on a commercial diet containing 4-Dimethylaminostilbene, 0.004%, from the age of 57 days to the respective days of their decapitations. Fresh cryostat serial sections of Zymbal glands were examined by histochemical methods for SDH, LDH and G6PDH 6, 11 and 17 weeks after the first injection. Either atypical hyperplasia of the acinar cells or microtumor was
more » ... s or microtumor was detected in the Zymbal glands of almost all treated rats 11 weeks after the first injection. An ear duct tumor was induced in all treated animals 17 weeks after treatment. SDH and G6PDH activities decreased progressively in the tumorigenesis, but moderate LDH activity remained in the tumor tissues. Biochemical determinations for LDH and MDH in the Zymbal glands harvested serially 4-20 weeks after the first injection of DMBA indicated that the quotient of LDH/MDH began to elevate 5-11 weeks after injection and elevated in the tumorigenesis owing to a progressively lower MDH. There have been numerous histo-and cytochemical observations on the enzymes of different tumors (2). These studies provide very useful information not only about the presence and activities of enzymes in relation to tumor growth, but also analysis of neoplastic transformation. Experimentally, in rats, special tumors in the auditory organs have been induced by the administration of aromatic hydrocarbons, aromatic amines, azo compounds or other chemical agents (7), and they are commonly called ear duct tumors. The induction of ear duct tumor with 7, l 2-Dimethylbenz(a)anthracene (DMBA) was greatly accelerated by feeding the animals a diet containing 4-Dimethylaminostilbene (DAS) ; none of the rats in these studies developed dual tumor growths at different locations (4). It would be reasonable to assume from our histological investigations that the ear duct tumor arises not from the squamous epithelium of the external auditory canal, but from cells which constitute the acini of the Zymbal gland. Systemic administration of DMBA and DAS evoked exclusively in the Zymbal gland the growth of tumors so minute as to be
doi:10.1267/ahc.12.361 fatcat:5beikgbijvcvvdufreioj23kvi