Suppression of Growth of DMBA-induced Mammary Cancers in Female Rats Fed on Coconut Oil Diets

Abstract

The effects of the semisynthetic diets containing a refined coconut oil upon the growth of DMBA-induced mammary cancers were investigated in 87 young adult female Sprague-Dawley rats. Eighty young female rats were maintained on a commercial pellets, CMF type of Oriental Yeast Company, and injected to a caudal vein with 3 mg of DMBA at the age of 55 and 58 days. In the ages of 85 to 145 days for promotion stage of the tumor growth, the experimental animals were distributed to 4 groups (Table 2) and fed on 4 different semisynthetic diets, respectively. The diets (Table 1) were isocaloric (395 Ca1/100g), although they Contained a refined oil (coconut oil or corn oil) at either 8(ordinary) or 20 (high) percentage. The rats were observed in 3 months after the first injection of the carcinogen. The time of appearance of the first palpable mammary cancer was dated from the first injection of DMBA (Incubation Time). All rats were sacrificed at the age of 145 days. Mammary cancers in a rat were counted in the gross at necropsy (Active Center). Total mammary cancers per an animal were weighed on a balance (Tumor Weight). All detectable mammary tumors were observed histologically, and the above-mentiond mammary cancers were verified by the histological examinations.