Effects of high corn oil diet on preneoplastic murine colons: prostanoid production and lipid composition.
In the present study, the effect of normal (5% by wt) and high (23.5% by wt) corn oil diets on prostanoid production and on the lipid composition of preneoplastic colonic epithelium was investigated. CF1 mice (female, 3-4-weeks-old) were fed a normal corn oil diet ad libitum and were treated with the colon carcinogen 1,2-dimethylhydrazine (DMH, 20 mg/kg/wk) or saline (control) for 24 wk. At this stage, all animals received the AIN-76 diet (normal corn oil) ad libitum. Following the last injection, half of the animals from each treatment group were randomly allocated to a high corn oil diet for 5 to 10 wk, whereas the remaining animals continued on the normal corn oil diet. After 5 wk of feeding, the colonic mucosa of carcinogen-treated animals had a higher level of bicyclic prostaglandin E2 (PGE2) than had the animals in the control groups; prostanoid synthesis in the colonic mucosa of control animals was unaffected by the high corn oil diet. Preneoplastic colonic mucosa of animals fed the high corn oil diet had a significantly higher level of PGE2 than corresponding control colonic mucosa. The 6-keto-prostaglandin F1 alpha/thromboxane B2 ratio was significantly lower in the DMH-treated groups than in the control groups, and was unaffected by dietary treatments. After 10 wk of feeding a particular diet, the differences in the fatty acid composition between the control and DMH-treated groups were minor. Our findings demonstrate that the preneoplastic colonic epithelium differs from that of normal epithelium with respect to prostanoid synthesis.
Robblee
N M
NM
Department of Foods and Nutrition, University of Manitoba, Winnipeg, Canada.
Bird
R P
RP
D019813:1,2-Dimethylhydrazine; D000818:Animals; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D003314:Corn Oil / Q000378:metabolism / Q000494:pharmacology*; D004127:Dimethylhydrazines; D015232:Dinoprostone / Q000096:biosynthesis; D011464:Epoprostenol / Q000096:biosynthesis; D005260:Female; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D051379:Mice; D008815:Mice, Inbred Strains; D011230:Precancerous Conditions / Q000378:metabolism* / Q000473:pathology; D011453:Prostaglandins / Q000032:analysis / Q000096:biosynthesis*; D013928:Thromboxane A2 / Q000096:biosynthesis
D004127:Dimethylhydrazines; D008055:Lipids; D011453:Prostaglandins; D013928:Thromboxane A2; D003314:Corn Oil; D011464:Epoprostenol; D019813:1,2-Dimethylhydrazine; D015232:Dinoprostone