The modifying potential of allyl sulfide (AS), indole-3-carbinol (13C) and carboxyethylgermanium sesquioxide (GE) on lesion development was examined in a wide-spectrum initiation model. Group 1-4 were treated sequentially with diethylnitrosamine (DEN) (100 mg/kg, i.p., single dose), N-methylnitrosourea (MNU) (20 mg/kg, i.p., four doses at days 2, 5, 8 and 11), and N,N-dibutylnitrosamine (DBN) (0.05% in drinking water during weeks 3 and 4). Groups 5-7 received vehicles without carcinogens during the initiation period. Group 8 served as the untreated control. After this initiating procedure, groups 2-7 were administered a diet containing 0.5% AS or I3C and 0.05% GE. All surviving animals were killed 40 weeks after the beginning of the experiment and the target organs were examined. The induction of GS-P+ hepatic foci in rats treated with carcinogens was significantly inhibited by treatment with all three compounds. AS treatment significantly decreased the incidence of hepatic hyperplastic nodules, adenoma of the lung and thyroid, and papillary or nodular hyperplasia of the urinary bladder. Administration of GE also significantly inhibited the development of hepatic nodules and adenoma of the lung and thyroid. However, I3C only inhibited the hyperplastic nodules of the liver. These results demorrstrated that this multia-organ initiation model could be useful in confirming organ-specific modification potential and, in addition, the inhibitory effect of AS, I3C and GE on Liver, lung, thyroid and urinary bladder carcinogenesis.
Bibliographical noteFunding Information:
The authors wish to thank Professor Kiyomi Sato of Hirosalti University, Hirosaki, for his generous gift of GST-P antibody, along with Mr Won Suk Jang, Miss Sun Joo Lee and Miss Mi Jung Eui for their excellent technical assistance. This study was supported by a National Project Grant from the Ministry of Sciences and Technology.