Fiber type- and fatty acid composition-dependent effects of high-fat diets on rat muscle triacylglyceride and fatty acid transporter protein-1 content.
Intramuscular triacylglyceride (TAG) is considered an independent marker of insulin resistance in humans. Here, we examined the effect of high-fat diets, based on distinct fatty acid compositions (saturated, monounsaturated or n-6 polyunsaturated), on TAG levels and fatty acid transporter protein (FATP-1) expression in 2 rat muscles that differ in their fiber type, soleus, and gastrocnemius; the relationship to whole body glucose intolerance was also studied. Compared with carbohydrate-fed rats, the groups subjected to any one of the high-fat diets consistently exhibited enhanced body weight gain and adiposity, elevated plasma free fatty acids and TAG in the fed condition, hyperinsulinemia, and glucose intolerance. TAG content was consistently higher in soleus than in gastrocnemius, but was only significantly elevated by the n-6 polyunsaturated-based diet. FATP-1 levels in soleus were double those in gastrocnemius muscle in carbohydrate-fed animals. High-fat diets caused an elevation in FATP-1 protein content in soleus, but a reduction in gastrocnemius. In conclusion, the hyperinsulinemic hyperlipidemic condition upregulates FATP-1 expression in soleus and downregulates that of gastrocnemius. Hypercaloric saturated, monounsaturated, or n-6 polyunsaturated lipid diets cause equivalent whole body insulin resistance in rats, but only an n-6 polyunsaturated acid-based diet triggers intramuscular TAG accumulation.
Marotta
Mario
M
Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Spain.
Ferrer-Martnez
Andreu
A
Parnau
Josep
J
Turini
Marco
M
Macé
Katherine
K
Gómez Foix
Anna M
AM
D000273:Adipose Tissue / Q000187:drug effects; D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002352:Carrier Proteins / Q000096:biosynthesis*; D004041:Dietary Fats / Q000032:analysis / Q000494:pharmacology*; D004043:Dietary Fiber / Q000494:pharmacology*; D004435:Eating; D050612:Fatty Acid Transport Proteins; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000032:analysis / Q000494:pharmacology*; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005951:Glucose Tolerance Test; D005989:Glycerides / Q000378:metabolism*; D006949:Hyperlipidemias / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D026901:Membrane Transport Proteins; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D002352:Carrier Proteins; D004041:Dietary Fats; D004043:Dietary Fiber; D050612:Fatty Acid Transport Proteins; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D005989:Glycerides; D007328:Insulin; D026901:Membrane Transport Proteins; C493570:Slc27a1 protein, rat