J Korean Diabetes Assoc.  2001 Dec;25(6):460-468.

The Effects of Uncoupling Protein 3 Overexpression on Glucose Metabolism in OLETF Rats in Vivo and Cultured Skeletal Muscle Cells in Vitro

Affiliations
  • 1Department of Internal Medicine, College of Medicine, University of Ulsan, Korea.
  • 2Asan Institute for Life Sciences and Technology, Korea.
  • 3Department of Internal Medicine, Keimyung University, Korea.
  • 4Department of Biochemistry, College of Medicine, University of Ulsan, Korea.

Abstract

BACKGROUND: UCP3 is a mitochondrial membrane protein expressed selectively in the skeletal muscle and brown adipose tissue. Since the skeletal muscle is the main organ determining insulin sensitivity in the body, it was hypothesized that UCP3 overexpression in skeletal muscle cells would improve glucose metabolism.
METHODS
An adenovirus-UCP3 was produced by a recombinant DNA method. OLETF rats were divided into 2 groups. Four rats were injected with the adenovirus- UCP3 (UCP3 group) and others were injected with the adenovirus (control group) in the skeletal muscle. The UCP3 group was provided with the same quantity of food as that consumed by the control group on the previous day. Insulin sensitivity was evaluated by the euglycemic hyperinsulinemic clamp method. In a separate experiment, glucose transport and glycogen synthesis we evaluated in C2C12 cells transfected with ether an adenovirus or the adenovirus-UCP3.
RESULTS
The insulin sensitivity improved significantly and the body weight decreased in the UCP3 group. The glucose transport and glycogen synthesis were higher in the UCP3-C2C12 skeletal muscle cells at the basal state. After insulin treatment, glucose transport and glycogen synthesis were also higher in the UCP3-C2C12 cells but the increments were reduced after treatment with wortmannin, a PI3K inhibitor.
CONCLUSION
Insulin sensitivity was higher in the UCP3-overexpressed OLETF rats in the in vivo study. UCP3 transfection also increased glucose transport and glycogen synthesis in the cultured skeletal muscle cells by a PI3K dependent mechanism.

Keyword

UCP3; Glucose transport; Glycogen synthesis; PI3K

MeSH Terms

Adenoviridae
Adipose Tissue, Brown
Animals
Body Weight
DNA, Recombinant
Ether
Glucose*
Glycogen
Insulin
Insulin Resistance
Metabolism*
Mitochondrial Membranes
Muscle, Skeletal*
Rats
Rats, Inbred OLETF*
Transfection
DNA, Recombinant
Ether
Glucose
Glycogen
Insulin
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