Dietary polyunsaturated fatty acids enhance hepatic AMP-activated protein kinase activity in rats.
Polyunsaturated fatty acids (PUFA) and a number of drugs (metformin, thiazolidinediones) and hormones (leptin, adiponectin) that activate AMP-activated protein kinase (AMPK) have been reported to improve insulin sensitivity. To determine whether PUFA activate AMPK, Sprague-Dawley rats were adapted to a 3h meal-feeding regimen using a fat-free diet (FFD) supplemented with fish oil (n-3) or triolein (n-9) for 7 days. No differences in hepatic AMPK activity were observed between the groups after 21h of fasting. On the other hand, hepatic AMPK phosphorylation was decreased in rats refed the FFD, the FFD+triolein, and the FFD+PUFA by 80%, 75%, and 50%, respectively, when assessed 2h after completion of a meal. In keeping with these changes, decreases in acetyl-CoA carboxylase phosphorylation and carnitine palmitoyl transferase-1 mRNA and increases in fatty acid synthase gene expression were greatest in rats fed the FFD and least in the PUFA-fed rats. The results indicate that dietary PUFA enhance hepatic AMPK activity in vivo, and implicate AMPK as a component of the nutrient-sensing mechanism through which dietary fatty acids and especially PUFA influence the regulation of hepatic lipid metabolism and gene expression.
Suchankova
Gabriela
G
Pennington Biomedical Research Center, Baton Rouge, LA, USA.
Tekle
Michael
M
Saha
Asish K
AK
Ruderman
Neil B
NB
Clarke
Steven D
SD
Gettys
Thomas W
TW
D055372:AMP-Activated Protein Kinases; D000284:Administration, Oral; D000818:Animals; D004042:Dietary Fats, Unsaturated / Q000378:metabolism*; D004789:Enzyme Activation; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D008099:Liver / Q000201:enzymology*; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins; D051381:Rats
D004042:Dietary Fats, Unsaturated; D005231:Fatty Acids, Unsaturated; D009097:Multienzyme Complexes; D011506:Proteins; C061401:SPAI-1 protein, Sus scrofa; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases