Effects of dietary primrose oil on mammary tumorigenesis induced by 7,12-dimethylbenz(a)anthracene.
The mammary tumor-promoting effect of a high-fat diet containing 20% evening primrose oil (PO) was compared to that of a 20% corn oil (CO) diet. Mammary tumors were induced in female Sprague-Dawley rats using 10 mg (Study 1) and 5 mg (Study 2) 7,12-dimethylbenz(a)anthracene (DMBA). The 10 mg dose of DMBA gave a total mammary tumor incidence of 47% in rats fed the PO diet and 80% for those fed the CO diet. When only adenocarcinomas were counted, the malignant mammary tumor incidences were 41% in rats fed the PO diet and 73% in rats fed the CO diet. In a second study using 5 mg DMBA to induce mammary tumors, total tumor incidences were 50% for PO-fed rats and 63% for those receiving a CO diet. Again, when only adenocarcinomas were counted, tumor incidences were 27% for PO- and 63% for CO-dieted rats. Analysis of plasma fatty acid profiles indicated that animals fed a 20% PO diet showed significant increases in 18:3 and 20:4 fatty acids and significant decreases in 16:0 and 18:1 compared to animals fed a 20% CO diet. These results indicate that the mammary tumor promoting effect of a diet containing 20% fat can be diminished by substituting PO for CO. Moreover, the promoting effect on mammary cancer by a high-fat diet could be depressed by feeding a source of gamma-linolenic acid (GLA).
D015127:9,10-Dimethyl-1,2-benzanthracene; D000230:Adenocarcinoma / Q000473:pathology*; D000818:Animals; D003314:Corn Oil / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology*; D005228:Fatty Acids, Essential / Q000494:pharmacology*; D005260:Female; D008041:Linoleic Acids; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D031665:Oenothera biennis; D010938:Plant Oils; D051381:Rats; D011919:Rats, Inbred Strains; D017965:gamma-Linolenic Acid
D004041:Dietary Fats; D005228:Fatty Acids, Essential; D008041:Linoleic Acids; D010938:Plant Oils; C028498:evening primrose oil; D015127:9,10-Dimethyl-1,2-benzanthracene; D017965:gamma-Linolenic Acid; D003314:Corn Oil