Dietary fat and selenium effects on ex vivo prostaglandin production in rat colon, kidney, and blood

The effects were determined of dietary fat and selenium (Se) levels on prostaglandin (PG) production in rat blood, kidney, and colon mucosa. For 30 weeks, male Wistar-derived MRC rats were prefed diets containing low (6 g/367 kcal) or high (20 g/367 kcal) levels of fat with one of three Se supplements from sodium selenite: 0.0, 0.1, or 2.0 ppm Se. PG production was stopped by adding aspirin immediately following removal of the blood, kidney, and colon samples. Separate samples were allowed to incubate 10 or 60 minutes before blockage of PG production for determination of ex vivo PG production. Prostaglandin E2 (PGE2), thromboxane B2, and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were measured by radioimmunoassay following separation on silicic acid columns. Basal levels of the three PGs were not influenced by diet. PGE2 production in the colon was highest in the group fed the high-fat diet that contained 2.0 ppm Se at 10 and 60 minutes, but PGE2 production in the blood and kidney were not altered by diet. Thromboxane B2 production in the rats' blood was higher in those prefed high-fat diets, but it was not influenced by dietary Se. Production of 6-keto-PGF1 alpha in the blood and thromboxane B2 and 6-keto-PGF1 alpha production by the kidney and colonic mucosa were not influenced by either dietary fat or Se.