The effects of dietary selenomethionine on polyamines and azoxymethane-induced aberrant crypts

We evaluated the effects of dietary selenomethionine supplementation on col onic polyamine levels and the ability of L-selenomethionine supplementation to modulate the carcinogenic activity of azoxymethane (AOM) in the rat col on, Four-week-old male F344 rats were treated with 15 mg/kg body weight of AOM once a week for 2 weeks. Dietary selenomethionine at a concentration of either I or ? ppm was administered in AIN-76A rodent diet to AOM-treated a nimals for 16 weeks. Aberrant crypt foci (ACF), precursor lesions of colon cancer, were investigated after the 16 week treatment course. Selenomethion ine given in the diet at 2 ppm markedly reduced the number of aberrant cryp t foci. The multiplicity of ACFs (i.e. the number of aberrant crypts/focus) anti the percentage of microadenomas were also affected by selenomethionin e in a dose dependent manner. However, evaluation of the colonic tissue pol yamine levels between control and treated groups showed no significant diff erence.. These results demonstrate that selenomethionine can modulate the d evelopment of AOM-induced premalignant lesions through a polyamine-independ ent mechanism. (C) 2000 Elsevier Science lreland Ltd. All rights reserved.