Premium
Dietary Conjugated Linoleic Acids Alter Serum IGF‐I and IGF Binding Protein Concentrations and Reduce Bone Formation in Rats Fed ( n ‐6) or ( n ‐3) Fatty Acids
Author(s) -
Li Yong,
Seifert Mark F.,
Ney Denise M.,
Grahn Mike,
Grant Alan L.,
Allen Kenneth G. D.,
Watkins Bruce A.
Publication year - 1999
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.1999.14.7.1153
Subject(s) - endocrinology , medicine , polyunsaturated fatty acid , weanling , linoleic acid , osteocalcin , conjugated linoleic acid , chemistry , fatty acid , biology , biochemistry , alkaline phosphatase , enzyme
A study was designed to examine the effects of dietary conjugated linoleic acid (CLA) on serum concentrations of insulin‐like growth factor‐I (IGF‐I) and IGF binding proteins (IGFBP) and the relationship of these factors to bone metabolism. Weanling male rats were fed AIN‐93G diet containing 70 g/kg of added fat for 42 days. Treatments included 0 g/kg or 10 g/kg of CLA and soybean oil (SBO) or menhaden oil + safflower oil (MSO) following a 2 × 2 factorial design. Serum IGFBP was influenced by dietary polyunsaturated fatty acid (PUFA) type (( n ‐6) and ( n ‐3)) and CLA ( p = 0.01 for 38–43 kDa bands corresponding to IGFBP‐3). CLA increased IGFBP level in rats fed SBO ( p = 0.05) but reduced it in those fed MSO ( p = 0.01). Rats fed MSO had the highest serum IGFBP‐3 level. Both ( n ‐3) fatty acids and CLA lowered ex vivo prostaglandin E 2 production in bone organ culture. In tibia, rats given CLA had reduced mineral apposition rate (3.69 vs. 2.79 μm/day) and bone formation rate (BFR) (0.96 vs. 0.65 μm 3 /μm 2 /day); however, the BFR tended to be higher with MSO. Dietary lipid treatments did not affect serum intact osteocalcin or bone mineral content. These results showed that dietary PUFA type and CLA modulate local factors that regulate bone metabolism.