title: Dietary ratio of (n-6)/(n-3) polyunsaturated fatty acids alters the fatty acid composition of bone compartments and biomarkers of bone formation in rats.
abstract: The effects of dietary polyunsaturated fatty acids (PUFA) on ex vivo bone prostaglandin E(2) (PGE(2)) production and bone formation rate were evaluated in rats. Weanling male Sprague-Dawley rats were fed AIN-93G diet containing 70 g/kg of added fat for 42 d. The dietary lipid treatments were formulated with safflower oil and menhaden oil to provide the following ratios of (n-6)/(n-3) fatty acids: 23.8 (SMI), 9.8 (SMII), 2.6 (SMIII), and 1.2 (SMIV). Ex vivo PGE(2) production in liver homogenates and bone organ cultures (right femur and tibia) were significantly lower in rats fed diets with a lower dietary ratio of (n-6)/(n-3) fatty acids than in those fed diets with a higher dietary ratio. Regression analysis revealed a significant positive correlation between bone PGE(2) and the ratio of arachidonic acid (AA)/eicosapentaenoic acid (EPA), but significant negative correlations between bone formation rate and either the ratio of AA/EPA or PGE(2) in bone. Activities of serum alkaline phosphatase isoenzymes, including the bone-specific isoenzyme (BALP), were greater in rats fed a diet high in (n-3) or a low ratio of (n-6)/(n-3), further supporting the positive action of (n-3) fatty acids on bone formation. These results demonstrated that the dietary ratio of (n-6)/(n-3) modulates bone PGE(2) production and the activity of serum BALP in growing rats.
authors.affiliation: Department of Food Science, Lipid Chemistry and Molecular Biology Laboratory, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Watkins
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: K G
authors.initials: KG
authors.lastname: Allen
authors.forename: W E
authors.initials: WE
authors.lastname: Hoffmann
authors.forename: M F
authors.initials: MF
authors.lastname: Seifert
mesh_terms: D000818:Animals; D015415:Biomarkers; D001835:Body Weight / Q000187:drug effects; D001842:Bone and Bones / Q000378:metabolism*; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D015232:Dinoprostone / Q000096:biosynthesis*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D015675:Osteocalcin / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D012450:Safflower Oil / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D015675:Osteocalcin; C033266:Menhaden oil; D012450:Safflower Oil; D015232:Dinoprostone