To clarify the detailed mechanism of preferential induction of male rodent liver cancer by aflatoxin B
1 (AFB
1), we investigated the effects of steroid hormones and inducers of cellular differentiation on the growth of Kagura-2 cells established from AFB
1-induced rat hepatoma. By the addition of 10
-5 M glucocorticoid (GC) hormones such as dexamethasone (DEX) and triamcinolone acetonide (TA), the colony formation of Kagura-2 cells in soft agar was stimulated about 16-fold of the control. Moreover, the cells showed the GC hormone-dependent growth in serum-free medium. In contrast, tamoxifen, sodium butyrate and N, N'-hexamethylene-bis-acetamide (HMBA) strongly inhibited the cell growth. Sex steroid hormones, estradiol and testosterone, slightly enchanced the cell growth. The present data obviously indicate that GC hormones play a critical role in the progression step of hepatocarcinogenesis by AFB
1.
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