PREVENTIVE EFFECTS OF POLYSACCHARIDES EXTRACTED FROM HUMAN TUBERCLE-BACILLI (SPECIFIC SUBSTANCE OF MARUYAMA) ON COLONIC CARCINOGENESIS IN RATS

Polysaccharides extracted from human tubercle bacilli (specific substa nce of Maruyama [SSM]) have been clinically applied with satisfactory results. Thymidylate synthetase (TS) and thymidine kinase (TK) are key enzymes in de novo and salvage pathways for pyrimidine nucleotide syn thesis. Well-and moderately well differentiated adenocarcinomas induce d with 1,2-dimethylhydrazine (DMH) are: widely distributed throughout the colorectal tract with high TK activity, and the poorly differentia ted type is mainly restricted in the proximal colon and the cecum with high TS activity in rats. Subcutaneously injecting the rats with SSM reduced TS activity in colonic nontumorous regions, but in the tumorou s regions it reduced TK activity compared with that of the DMH-treated rats without SSM treatment. SSM is suggested to reduce the colorectal carcinogenesis induced with DMH by inhibiting DNA synthesis in a de n ovo pathway, and to suppress the development of the tumors by decreasi ng DNA synthesis in the salvage pathway in rats.