Dietary cholesterol and experimental mammary cancer development.
The effect of high- and low-fat diets, with and without cholesterol supplementation, on the development of N-methylnitrosourea (NMU)-induced mammary tumors was assessed. Diets consisting of 1. high fat (HF) (20% lard), 2. HF + cholesterol, 3. low fat (LF) (4% lard) + cholesterol, and 4. LF were fed to F344 female rats (24 animals/group) 2 days after NMU administration, and cumulative mammary tumor incidence was monitored for a total of 26 weeks. Animals fed HF diets exhibited significantly greater tumor incidences and numbers of tumors/animal than did animals fed LF diets (p less than .0001), regardless of whether cholesterol was present in the diet. These results are consistent with the hypothesis that the mammary-tumor promoting effects of HF diets are exerted primarily by the triglyceride fraction rather than by the nonsaponifiable (sterol) fraction of total dietary fat.
D000230:Adenocarcinoma / Q000139:chemically induced* / Q000473:pathology; D000818:Animals; D002791:Cholesterol, Dietary / Q000009:adverse effects*; D004041:Dietary Fats / Q000008:administration & dosage / Q000009:adverse effects*; D004357:Drug Synergism; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology; D008770:Methylnitrosourea; D009607:Nitrosourea Compounds; D051381:Rats; D011916:Rats, Inbred F344; D014280:Triglycerides / Q000633:toxicity
D002791:Cholesterol, Dietary; D004041:Dietary Fats; D009607:Nitrosourea Compounds; D014280:Triglycerides; D008770:Methylnitrosourea