cAMP-dependent signaling regulates the adipogenic effect of n-6 polyunsaturated fatty acids
Research output: Contribution to journal › Journal article › Research › peer-review
The effect of n-6 polyunsaturated fatty acids (n-6 PUFAs) on adipogenesis and obesity is controversial. Using in vitro cell culture models, we show that n-6 PUFAs was pro-adipogenic under conditions with base-line levels of cAMP, but anti-adipogenic when the levels of cAMP were elevated. The anti-adipogenic action of n-6 PUFAs was dependent on a cAMP-dependent protein kinase-mediated induction of cyclooxygenase expression and activity. We show that n-6 PUFAs were pro-adipogenic when combined with a high carbohydrate diet, but non-adipogenic when combined with a high protein diet in mice. The high protein diet increased the glucagon/insulin ratio, leading to elevated cAMP-dependent signaling and induction of cyclooxygenase-mediated prostaglandin synthesis. Mice fed the high protein diet had a markedly lower feed efficiency than mice fed the high carbohydrate diet. Yet, oxygen consumption and apparent heat production were similar. Mice on a high protein diet had increased hepatic expression of PGC-1alpha (peroxisome proliferator-activated receptor gamma coactivator 1alpha) and genes involved in energy-demanding processes like urea synthesis and gluconeogenesis. We conclude that cAMP signaling is pivotal in regulating the adipogenic effect of n-6 PUFAs and that diet-induced differences in cAMP levels may explain the ability of n-6 PUFAs to either enhance or counteract adipogenesis and obesity.
Original language | English |
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Journal | Journal of Biological Chemistry |
Volume | 283 |
Issue number | 11 |
Pages (from-to) | 7196-205 |
Number of pages | 9 |
ISSN | 0021-9258 |
DOIs | |
Publication status | Published - 2008 |
Bibliographical note
Keywords: 3T3-L1 Cells; Adipocytes; Adipogenesis; Animals; Carbohydrates; Cyclic AMP; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Male; Mice; Mice, Inbred C57BL; Models, Biological; Obesity; Signal Transduction; Urea
ID: 21338378