Overexpression of regucalcin suppresses gene expression of insulin signaling-related proteins in cloned rat hepatoma H4-II-E cells: Involvement of insulin resistance

  • Authors:
    • Chikage Nakashima
    • Masayoshi Yamaguchi
  • View Affiliations

  • Published online on: November 1, 2007     https://doi.org/10.3892/ijmm.20.5.709
  • Pages: 709-716
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Abstract

Overexpression of regucalcin has been shown to enhance glucose utilization and lipid production in the cloned rat hepatoma H4-II-E cells in vitro, and it induces insulin resistance. The effect of regucalcin on the gene expression of insulin signaling-related proteins was investigated in the cloned rat hepatoma H4-II-E cells overexpressing regucalcin in vitro. The hepatoma cells (wild-type) and stable regucalcin/ pCXN2-transfected cells (transfectants) were cultured for 72 h in a medium containing 10% fetal bovine serum (FBS) to obtain subconfluent monolayers. Cells with subconfluency were cultured for 24, 48, or 72 h in a medium containing either vehicle or insulin (10−9-10−7 M) with or without supplementation of glucose (10, 25, or 50 mg/ml of medium). The expression of rat insulin receptor (Insr), phosphatidylinositol 3-kinase (PI3K), glucose transporter 2 (GLUT 2), or glyceroaldehyde-3-phosphate dehydrogenase (G3PDH) mRNAs was examined using reverse transcription-polymerase chain reaction analysis with specific primers. GLUT 2 mRNA expression was significantly increased in the transfectants, while Insr, PI3K, and G3PDH mRNA levels were not significantly changed in the transfectants. Culture with insulin (10−8 or 10−7 M) caused a significant increase in PI3K mRNA levels in wild-type cells cultured for 24 or 48 h, while it had no effect on Insr mRNA levels. The supplementation of glucose (10, 25, or 50 mg/ml) caused a significant increase in Insr and PI3K mRNA levels in wild-type cells. The effect of insulin or glucose supplementation on these gene expression levels was not seen in the transfectants. The combination of insulin (10−7 M) and glucose (50 mg/ml) caused a significant increase in Ins and PI3K mRNA levels in wild-type cells. Such an effect was not seen in the transfectants. Culture with insulin or glucose supplementation failed to have a significant effect on GLUT2 and G3PDH mRNA levels in the wild-type cells or transfectants. This study demonstrates that overexpression of regucalcin suppresses the enhancing effect of insulin or glucose on the gene expression of insulin signaling-related proteins in the cloned rat hepatoma H4-II-E cells.

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november 2007
Volume 20 Issue 5

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Nakashima C and Nakashima C: Overexpression of regucalcin suppresses gene expression of insulin signaling-related proteins in cloned rat hepatoma H4-II-E cells: Involvement of insulin resistance. Int J Mol Med 20: 709-716, 2007
APA
Nakashima, C., & Nakashima, C. (2007). Overexpression of regucalcin suppresses gene expression of insulin signaling-related proteins in cloned rat hepatoma H4-II-E cells: Involvement of insulin resistance. International Journal of Molecular Medicine, 20, 709-716. https://doi.org/10.3892/ijmm.20.5.709
MLA
Nakashima, C., Yamaguchi, M."Overexpression of regucalcin suppresses gene expression of insulin signaling-related proteins in cloned rat hepatoma H4-II-E cells: Involvement of insulin resistance". International Journal of Molecular Medicine 20.5 (2007): 709-716.
Chicago
Nakashima, C., Yamaguchi, M."Overexpression of regucalcin suppresses gene expression of insulin signaling-related proteins in cloned rat hepatoma H4-II-E cells: Involvement of insulin resistance". International Journal of Molecular Medicine 20, no. 5 (2007): 709-716. https://doi.org/10.3892/ijmm.20.5.709