Cited by 1,096Adipose Tissue and MetabolismMuscle metabolism and nutritionMetabolism, Diabetes, and Cancer

Skeletal muscle fatty acid metabolism in association with insulin resistance, obesity, and weight loss

Kelley, David E., Goodpaster, Bret, Wing, Rena R., Simoneau, Jean-Aime·1999·American Journal of Physiology-Endocrinology and Metabolism

Abstract

The current study was undertaken to investigate fatty acid metabolism by skeletal muscle to examine potential mechanisms that could lead to increased muscle triglyceride in obesity. Sixteen lean and 40 obese research volunteers had leg balance measurement of glucose and free fatty acid (FFA) uptake (fractional extraction of [9,10 (3)H]oleate) and indirect calorimetry across the leg to determine substrate oxidation during fasting and insulin-stimulated conditions. Muscle obtained by percutaneous biopsy had lower carnitine palmitoyl transferase (CPT) activity and oxidative enzyme activity in obesity (P < 0.05). During fasting conditions, obese subjects had an elevated leg respiratory quotient (RQ, 0.83 +/- 0.02 vs. 0.90 +/- 0.01; P < 0.01) and reduced fat oxidation but similar FFA uptake across the leg. During insulin infusions, fat oxidation by leg tissues was suppressed in lean but not obese subjects; rates of FFA uptake were similar. Fasting values for leg RQ correlated with insulin sensitivity (r = -0.57, P < 0.001). Thirty-two of the obese subjects were restudied after weight loss (WL, -14.0 +/- 0.9 kg); insulin sensitivity and insulin suppression of fat oxidation improved (P < 0.01), but fasting leg RQ (0.90 +/- 0.02 vs. 0.90 +/- 0.02, pre-WL vs. post-WL) and muscle CPT activity did not change. The findings suggest that triglyceride accumulation in skeletal muscle in obesity derives from reduced capacity for fat oxidation and that inflexibility in regulating fat oxidation, more than fatty acid uptake, is related to insulin resistance.

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Crossref · 10.1152/ajpendo.1999.277.6.e1130

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61 of 61 references verified0 citation errors · 0 not checkable

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  • Under euglycemic-hyperinsulinemic clamp conditions, insulin-resistant states are associated with impaired metabolic flexibility to glucose.

    “In those studies, insulin-resistant states are clearly associated with impaired metabolic flexibility to glucose (MetFlex-glu).”
  • Reduced mitochondrial oxidative capacity further impairs skeletal muscle oxidation, contributing to the development of insulin resistance commonly associated with obese individuals.

    “Consequently, reduced mitochondrial oxidative capacity further impairs skeletal muscle oxidation, contributing to the development of insulin resistance commonly associated with obese individuals [53].”
  • Several studies report decreased fat oxidation in skeletal muscle independent of plasma free fatty acid concentration.

    “Several studies have reported decreased fat oxidation in skeletal muscle, independent of the plasma FFA concentration [100–102].”

    From Pathogenesis of insulin resistance in skeletal muscle (2010) · cites this paper as [100]

  • In one study comparing leg muscle fat oxidation between obese and lean individuals, the rate of fatty acid oxidation was reduced in the obese group despite similar arterial free fatty acid concentrations.

    “In one study that compared muscle fat oxidation across the leg in obese (BMI = 34 kg/m2) compared to lean (BMI = 23 kg/m2) individuals, the rate of fatty acid oxidation was reduced in the obese group despite similar arterial FFA concentrations [100].”

    From Pathogenesis of insulin resistance in skeletal muscle (2010) · cites this paper as [100]

  • Metabolic flexibility assessed by the ability to switch from fat to carbohydrate oxidation is usually impaired during a hyperinsulinemic clamp in insulin-resistant subjects.

    “The metabolic flexibility assessed by the ability to switch from fat to carbohydrate oxidation is usually impaired during a hyperinsulinemic clamp in insulin-resistant subjects; however, this “metabolic inflexibility” is mostly the consequence of impaired cellular glucose uptake.”

    From Metabolic flexibility and insulin resistance (2008) · cites this paper as [24]

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Authors
Kelley, D. E., Goodpaster, B., Wing, R. R., & Simoneau, J.-A.
Affiliations
  • Pediatrics and Genetics (US)
  • University of Pittsburgh (US)
  • Division of Kinesiology, Department of Social and Preventive Medicine, Laval University, Ste-Foy, Quebec, Canada G1K 7P4
Venue
American Journal of Physiology-Endocrinology and Metabolism
Published
1999-12-01
Volume
277
Issue
6
Pages
E1130-E1141
ISSN
  • 0193-1849 (ISSN-L)
  • 1522-1555
OpenAlex
W2216710583
Cited by
1,096
References
60
Citations by year
2026: 13 · 2025: 39 · 2024: 34 · 2023: 43 · 2022: 43 · 2021: 50 · 2020: 45 · 2019: 48 · 2018: 46 · 2017: 41 · 2016: 38 · 2015: 39 · 2014: 40 · 2013: 54 · 2012: 48
FWCI
9.39
Type
journal article
Language
en
Open access
closed
Locations
  • American Journal of Physiology-Endocrinology and Metabolism (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (5p30dk046204-15)
  • National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK49200-02, 1P30DK-46204, R01DK049200)
  • National Center for Research Resources (M01RR000056)
Topics
  • Health Sciences › Medicine › Physiology › Adipose Tissue and Metabolism
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
Keywords
insulin resistance, obesity, weight loss, fat oxidation, free fatty acid uptake, carnitine palmitoyltransferase, respiratory quotient, insulin sensitivity, substrate oxidation
MeSH terms
Adult, Arteries, Blood Glucose, Calorimetry, Indirect, Diet, Reducing, Postural Balance, Fasting, Fatty Acids, Female, Glucose, Humans, Hypoglycemic Agents, Insulin, Insulin Resistance, Leg, Male, Middle Aged, Obesity, Veins, Weight Loss, Muscle, Skeletal

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