Brief food restriction increases FA oxidation and glycogen synthesis under insulin-stimulated conditions.
To determine the effects of brief food restriction on fatty acid (FA) metabolism, hindlimbs of F344/BN rats fed either ad libitum (AL) or food restricted (FR) to 60% of baseline food intake for 28 days were perfused under hyperglycemic-hyperinsulinemic conditions (20 mM glucose, 1 mM palmitate, 1,000 microU/ml insulin, [3-(3)H]glucose, and [1-(14)C]palmitate). Basal glucose and insulin levels were significantly lower (P < 0.05) in FR vs. AL rats. Palmitate uptake (34.3 +/- 2.7 vs. 24.5 +/- 3.1 nmol/g/min) and oxidation (3.8 +/- 0.2 vs. 2.7 +/- 0.3 nmol.g(-1).min(-1)) were significantly higher (P < 0.05) in FR vs. AL rats, respectively. Glucose uptake was increased in FR rats and was accompanied by significant increases in red and white gastrocnemius glycogen synthesis, indicating an improvement in insulin sensitivity. Although muscle triglyceride (TG) levels were not significantly different between groups, glucose uptake and total preperfusion TG concentration were negatively correlated (r(2) = 0.27, P < 0.05). In conclusion, our results show that under hyperglycemic-hyperinsulinemic conditions, brief FR resulted in an increase in FA oxidative disposal that may contribute to the improvement in insulin sensitivity.
Tucker
Michelle Z
MZ
Department of Kinesiology and University of Southern California Diabetes Research Center, University of Southern California, Los Angeles, California 90089, USA.
Turcotte
Lorraine P
LP
D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D015153:Blotting, Western; D002250:Carbon Radioisotopes; D002352:Carrier Proteins / Q000032:analysis; D002149:Energy Intake / Q000502:physiology*; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005947:Glucose / Q000493:pharmacokinetics; D006003:Glycogen / Q000096:biosynthesis*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000737:chemistry / Q000378:metabolism; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009929:Organ Size; D010084:Oxidation-Reduction; D010168:Palmitates / Q000378:metabolism* / Q000493:pharmacokinetics; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344; D002787:Sterol Esterase / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
D002250:Carbon Radioisotopes; D002352:Carrier Proteins; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D007004:Hypoglycemic Agents; D007328:Insulin; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010168:Palmitates; D014280:Triglycerides; D006003:Glycogen; D002787:Sterol Esterase; D005947:Glucose