Effect of dietarily provided linoleic and α-linolenic acid on the function of rat peritoneal macrophages

Abstract

The objective of this study was to determine whether the function of the macrophage can be influenced by a diet rich in α-linolenic acid, a fatty acid known to lead to a markedly reduced level of prostaglandin synthesis. Rats were fed purified diets containing all essential nutrients and differing only in the source of fat. A diet containing 10% corn oil provided a low ratio of α-linolenic to linoleic acid, while one containing 10% linseed oil provided a high ratio. Two macrophage activities reported to be influenced by prostaglandins, phagocytosis and arginase activity, were examined in peritoneal macrophages. Phagocytic ability, as determined by uptake of yeast and carbon particles, was examined in macrophages from rats fed the diets for 6 weeks after weaning and was found not to differ between the 2 groups. Arginase activity was examined in macrophages from rats fed the diets for 4 weeks after weaning, but which were born to females fed the diets from the time the latter were weanlings. Arginase activity was found to be significantly higher in the corn oil-fed group. This is consistent with reports that prostaglandins are involved in the induction of arginase in peritoneal macrophages.