Effect of coffee on carcinogenicity of cycasin

RECENTLY several epidemiological investigations have been reported, showing an association between coffee drinking and cancer of the lower urinary tract (Cole, 1971; Fraumeni, Scotto and Dunham, 1971; Bross and Tidings, 1973; Simon, Yen and Cole, 1975), and renal pelvis and ureter (Schmauz and Cole, 1974). Shennan (1973) produced a strong correlation between coffee consumption and national mortality rates from renal cancer. Armstrong, Garrod and Doll (1976), however, found no association between coffee drinking and the incidence of renal cancer. To study the carcinogenic activity of coffee, we started the following experiment, in which rats received a solution of coffee instead of drinking water for a long time, or coffee solution accompanied by a single low dose of cycasin. Four groups of Sprague-Dawley rats, 3 weeks old, of both sexes, were used as experimental groups. Group I.-IO male and 10 female rats were given coffee solution ad libitum instead of drinking water until the end of the experiment (480 days). To prepare the coffee solution, 2 g of Brazil coffee powder was immersed in 100 ml of boiling tap water for 5 min; the solution was then cooled and filtered with a cotton cloth. The strength of the coffee solution thus prepared was approximately equal to that of coffee normally drunk by man. Group I.-10 male and 10 female rats received coffee solution for the first 120 days, on the 12 1st day they were given cycasin 150 mg/kg by stomach tube, and Accepted 9 November 1976