Role of high-fat diet in tumorigenesis in C57BL/1 mice.
To determine if high contents of polyunsaturated fatty acids and estrogen might induce tumor formation in certain tissues of animals and to determine if the contents of the different classes of lipids in susceptible tissues would be changed, mice from the inbred C57BL/1 strain were fed the following diets: 1) Purina Laboratory Chow only (diet 1), which served as control; 2) Purina Laboratory Chow supplemented with corn oil and oleic acid (diet II); and 3) Purina Laboratory Chow supplemented with corn oil and estrogen (diet III). Although C57BL/1 mice are generally resistant to tumor formation, the present study showed that 8% of the mice maintained on diet II developed histologically confirmed adenocarcinoma of the colon, which metastasized to the lung and muscle. No macroscopic tumors were seen in mice maintained on diet III; however, fatty livers were seen in mice from this group (litters 5/313, 5/310). Total lipid and cholesterol contents in 6- and 12-month-old experimental mice were significantly higher than those in controls but not in older animals. In the pituitary glands of the 18- and 21-month-old control mice, total cholesterol content seemed higher than that of the experimental mice. Only livers of 12-month-old experimental mice showed significantly lower phospholipid content than that of the controls. Only the triglyceride content of livers from 18-month-old experimental mice was significantly higher than that of the controls. Finally, the ratio of saturated to unsaturated free fatty acids in livers of experimental mice was significantly altered from that of the control mice.
D000230:Adenocarcinoma / Q000209:etiology*; D000818:Animals; D003110:Colonic Neoplasms / Q000209:etiology*; D004041:Dietary Fats / Q000009:adverse effects*; D004958:Estradiol / Q000009:adverse effects*; D005230:Fatty Acids, Nonesterified / Q000032:analysis; D005231:Fatty Acids, Unsaturated / Q000009:adverse effects*; D008055:Lipids / Q000032:analysis; D008099:Liver / Q000032:analysis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000209:etiology; D010902:Pituitary Gland / Q000032:analysis
D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D004958:Estradiol