EFFECT OF REPLACING A HIGH LINOLEATE OIL WITH A LOW LINOLEATE, HIGH ALPHA-LINOLENATE OIL, AS COMPARED WITH SUPPLEMENTING EPA OR DHA, ON REDUCING LIPID MEDIATOR PRODUCTION IN RAT POLYMORPHONUCLEAR LEUKOCYTES

The fatty acid composition of rat polymorphonuclear leukocytes (PMN) w as modified by diets supplemented with a high linoleate (LA) safflower oil (76% LA), mixtures of eicosapentaenoate (EPA) and safflower oil ( EPA(20) containing 20% EPA and 61% LA, EPA(40) containing 40% EPA and 46% LA), mixtures of docosahexaenoate (DHA) and safflower oil (DHA(20) containing 20% DHA and 61% LA, DHA(40) containing 40% DHA and 46% LA) or a high alpha-linolenate (alpha-LNA) perilla oil (57% alpha-LNA and 13% LA), and then lipid mediator production in casein-induced periton eal PMN were compared. EPA and DNA were relatively ineffective in redu cing platelet-activating factor (PAF) production; a statistically sign ificant reduction was observed only in tile DHA(40) group. In contrast , perilla ail reduced PAF production by 50% as compared with safflower oil. Arachidonate (AA) in the PAP precursor, 1-alkyl-2-acyl-glyceroph osphocholine, was roughly correlated with PAF production, but EPA and DBA in the precursor lipid were relatively unrelated, On the other han d, both PGE(2) and LTB4, production correlated positively with AA and negatively with EPA and DHA in PMN phospholipids; EPA tended to be som ewhat more effective than DHA in reducing PGE(2) and LTB4 formation; t he activity of perilla oil was no less than EPA(20), Thus, replacing s afflower oil with perilla oil was no less effective than supplementing safflower oil with EPA or DEW (at 40% of total fatty acids) in reduci ng lipid mediator production in rat PMN.