Chronic ethanol consumption resulting in the downregulation of insulin receptor-beta subunit, insulin receptor substrate-1, and glucose transporter 4 expression in rat cardiac muscles.
The objective of this study was to investigate the effect of chronic ethanol intake on the expression of insulin receptor beta subunit (IR-beta), insulin receptor substrate-1 (IRS-1), and glucose transporter 4 (Glut4) in rat cardiac muscle. Forty-eight male Wistar rats were randomly classified into four groups and to each group, ethanol was administered daily at the respective doses of 0 (control, C), 0.5 g kg(-1) (low ethanol, L), 2.5 g kg(-1) (middle ethanol, M), and 5 g kg(-1) (high ethanol, H). Twenty-two weeks later, the rats were anesthetized, and the left ventricle muscles were excised. The IR-beta, IRS-1, and Glut4 mRNA levels in the cardiac muscle tissues were detected by reverse-transcription polymerase chain reaction (RT-PCR); the IR-beta, tyrosine phosphorylation of IR-beta (PY-IR-beta), IRS-1, tyrosine phosphorylation of IRS-1 (PY-IRS-1), and Glut4 protein levels were measured by Western blotting. Compared to the control group, the IR-beta, IRS-1, and Glut4 mRNA levels in groups H and M decreased remarkably. In addition, the protein levels of IR-beta, IRS-1, and Glut4 showed a corresponding decline in ethanol-treated groups, especially in group H. Moreover, the PY-IR-beta and PY-IRS-1 protein levels decreased in the hearts of ethanol-treated rats with corresponding changes in the IR-beta and IRS-1 protein levels. The present study showed that chronic ethanol intake could downregulate the expression levels of IR-beta, IRS-1, and Glut4 in rat cardiac muscles.
Limin
Tian
T
Department of Endocrinology, Provincial Hospital affiliated to Shandong University, Wenhua Road, Jinan 250021, China.
Hou
Xiaolei
X
Liu
Jing
J
Zhang
Xiujuan
X
Sun
Nannan
N
Gao
Ling
L
Zhao
Jiajun
J
D000818:Animals; D015153:Blotting, Western; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D051275:Glucose Transporter Type 4 / Q000096:biosynthesis*; D006321:Heart / Q000187:drug effects; D055504:Insulin Receptor Substrate Proteins / Q000096:biosynthesis*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D011972:Receptor, Insulin / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002492:Central Nervous System Depressants; D051275:Glucose Transporter Type 4; D055504:Insulin Receptor Substrate Proteins; C495694:Slc2a4 protein, rat; D000431:Ethanol; D012313:RNA; D011972:Receptor, Insulin