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Cited by 314Metabolism, Diabetes, and CancerProtein Kinase Regulation and GTPase SignalingDiabetes, Cardiovascular Risks, and Lipoproteins

Alterations in the Expression and Cellular Localization of Protein Kinase C Isozymes ε and θ Are Associated With Insulin Resistance in Skeletal Muscle of the High-Fat–Fed Rat

Schmitz-Peiffer, Carsten, Browne, Carol L, Oakes, Nicholas D, Watkinson, Allan, Chisholm, Donald J, Kraegen, Edward W, Biden, Trevor J·1997·Diabetes
DOI 10.2337/diab.46.2.169
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Abstract

We have tested the hypothesis that changes in the levels and cellular location of protein kinase C (PKC) isozymes might be associated with the development of insulin resistance in skeletal muscles from the highfat–fed rat. Lipid measurements showed that triglyceride and diacylglycerol, an activator of PKC, were elevated four- and twofold, respectively. PKC activity assays indicated that the proportion of membraneassociated calcium-independent PKC was also increased. As determined by immunoblotting, total (particulate plus cytosolic) PKC α, ε, and ζ levels were not different between control and fat-fed rats. However, the ratio of particulate to cytosolic PKC ε in red muscles from fat-fed rats was increased nearly sixfold, suggesting chronic activation. In contrast, the amount of cytosolic PKC θ was downregulated to 45% of control, while the ratio of particulate to cytosolic levels increased, suggesting a combination of chronic activation and downregulation. Interestingly, while insulin infusion in glucose-clamped rats increased the proportion of PKC θ in the particulate fraction of red muscle, this was potentiated by fat-feeding, suggesting that the translocation is a consequence of altered lipid flux rather than a proximal event in insulin signaling. PKC ε and θ measurements from individual rats correlated with triglyceride content of red gastrocnemius muscle; they did not correlate with plasma glucose, which was not elevated in fat-fed rats, suggesting that they were not simply a consequence of hyperglycemia. Our results suggest that these specific alterations in PKC ε and PKC θ might contribute to the link between increased lipid availability and muscle insulin resistance previously described using high-fat–fed rats.

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  • Increased PKC-β and δ activity has been reported in insulin-resistant states and can be induced during lipid infusion.

    “Increased activity of protein kinase C (PKC-β and δ has been reported in insulin resistant states and can be induced during lipid infusion [174, 175].”

    From Pathogenesis of insulin resistance in skeletal muscle (2010) · cites this paper as [174]

  • GLUT4 is the insulin-regulatable glucose transporter in skeletal muscle, has a Km of about 5 mmol/L close to plasma glucose, and is associated with HK-II.

    “GLUT4, the insulin regulatable transporter, is found in skeletal muscle, has a Km of approximately 5 mmol/L, which is close to that of the plasma glucose concentration, and is associated with HK-II [173, 174].”

    From Pathogenesis of insulin resistance in skeletal muscle (2010) · cites this paper as [174]

  • In rodents, a high-fat diet increases the concentration of diacylglycerol in muscles and activates novel PKCs.

    “In rodents, a high-fat diet increased the concentration of diacylglycerol in muscles and activated novel PKCs.36”

    From Lipid-induced insulin resistance: unravelling the mechanism (2010) · cites this paper as [36]

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Authors
Schmitz-Peiffer, C., Browne, C. L., Oakes, N. D., Watkinson, A., Chisholm, D. J., Kraegen, E. W., & Biden, T. J.
Affiliations
  • Garvan Institute of Medical Research Sydney, Australia
  • Garvan Institute of Medical Research (AU)
ORCID
Venue
Diabetes
Publisher
American Diabetes Association
Published
1997-02-01
Volume
46
Issue
2
Pages
169-178
ISSN
  • 0012-1797 (ISSN-L)
  • 1939-327X
DOI
10.2337/diab.46.2.169
OpenAlex
W2146243104
Cited by
314
References
0
Citations by year
2026: 4 · 2025: 5 · 2024: 5 · 2023: 1 · 2022: 3 · 2021: 5 · 2020: 6 · 2019: 6 · 2018: 3 · 2017: 5 · 2016: 5 · 2015: 13 · 2014: 3 · 2013: 12 · 2012: 11
FWCI
4.36
Type
journal article
Language
en
Open access
closed
Locations
  • Diabetes (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Kinase Regulation and GTPase Signaling
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes, Cardiovascular Risks, and Lipoproteins
Keywords
protein kinase C, protein kinase C epsilon, PKC theta, insulin resistance, skeletal muscle, high-fat diet, diacylglycerol, triglycerides, PKC translocation, red muscle, lipid availability, insulin signaling, gastrocnemius
MeSH terms
Animals, Cell Compartmentation, Cytosol, Dietary Fats, Insulin, Insulin Resistance, Isoenzymes, Membranes, Protein Kinase C, Rats, Wistar, Muscle, Skeletal, Rats

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