|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1997 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1996 : ¥1,100,000 (Direct Cost : ¥1,100,000)
The effect of alpha-carotene, beta-carotene, palm carotene and green tea polyphenols (GTP) on the progression stage of pancreatic carcinogenesis after rapid production of ductal lesions were studied in Syrian hamsters. Dose threshold inhibitory effects were noted for beta-carotene, 25 ppm and palm caratene, 40 ppm which includes 25 ppm beta-carotene reducing the numbers of putative preneoplastic lesions of duct epithelial hyperplasia, atypical hyperplasia, as well as carcinoma in situ and invasive carcinomas. GTP at deses of 500 and 5000 ppm, but not 100 ppm, also significantly decreased the numbers of hyperplasia and total duct lesions. Combined administration of 40 ppm palm carotene and 50 ppm GTP similarly inhibited the lesion development. alpha-Carotene, however, did not affect pancreatic carcinogenesis. These results suggest that chemopreventive effects are exerted by beta-carotene and GTP above critical doses and that combined administration of palm carotene and GTP might be a candidate chemoprevention strategy for pancreatic cancer in man.