Possible mechanisms for the differential effects of high linoleate safflower oil and high alpha-linolenate perilla oil diets on platelet-activating factor production by rat polymorphonuclear leukocytes.
As compared with high dietary linoleate safflower oil, high dietary alpha-linolenate perilla oil decreased platelet-activating factor (PAF) production by nearly half in calcium ionophore (CaI)-stimulated rat polymorphonuclear leukocytes (PMN). In the CaI-stimulated PMN from the perilla oil group, the accumulated amount of arachidonate (AA) plus eicosapentaenoate (EPA) was 30% less and that of lyso-PAF was 50% less, indicating that the decreased availability of lyso-PAF is a factor contributing to the relatively low PAF production. Consistently, eicosatetraynoic acid (ETYA), a dual inhibitor of cyclooxygenase and lipoxygenase, increased free fatty acids (FFA) and decreased PAF production possibly by decreasing the availability of lyso-PAF. Although, leukotrienes (LTs) have been proposed to stimulate PAF production synergistically, a potent LTB4 receptor antagonist, ONO-4057, decreased the formation of free fatty acids and LTB4, but stimulated PAF production somewhat, indicating that LTB4 may not stimulate PAF production in PMN. Lysophospholipid-induced transacylase (CoA-independent transacylase) activity in PMN homogenates was 25-30% lower in the perilla oil group but no significant differences were observed in the lyso-PAF acetyltransferase and PAF acetylhydrolase activities between the two dietary groups. Thus, decreased transacylase activity is another factor associated with the relatively low PAF production in the perilla oil group.
Oh-hashi
K
K
Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
Takahashi
T
T
Watanabe
S
S
Kobayashi
T
T
Okuyama
H
H
D000217:Acyltransferases / Q000378:metabolism; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology; D019787:Linoleic Acid / Q000008:administration & dosage; D008297:Male; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism*; D010666:Phenylpropionates / Q000494:pharmacology; D010938:Plant Oils; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018102:Receptors, Leukotriene B4 / Q000037:antagonists & inhibitors; D012450:Safflower Oil / Q000008:administration & dosage; D017962:alpha-Linolenic Acid / Q000008:administration & dosage
D004042:Dietary Fats, Unsaturated; D005230:Fatty Acids, Nonesterified; D007476:Ionophores; C029271:O-deacetyl platelet activating factor; D010666:Phenylpropionates; D010938:Plant Oils; D010972:Platelet Activating Factor; D018102:Receptors, Leukotriene B4; D017962:alpha-Linolenic Acid; C067523:ONO-LB 457; D000001:Calcimycin; C058216:perilla seed oil; D012450:Safflower Oil; D019787:Linoleic Acid; D000217:Acyltransferases; C039766:arachidonyl transacylase