Exenatide prevents fat-induced insulin resistance and raises adiponectin expression and plasma levels.
BACKGROUND
Exenatide (exendin-4) can reduce blood glucose levels, increase insulin secretion and improve insulin sensitivity through mechanisms that are not completely understood.


METHODS
In the present study, we examined the effects of exenatide treatment on glucose tolerance (intravenous glucose tolerance test), insulin sensitivity (euglycaemic-hyperinsulinaemic clamps), insulin signalling (insulin receptor substrate 1 tyrosine phosphorylation) and adipocytokine levels (visfatin and adiponectin) in high fat-fed rats.


RESULTS
Administration of exenatide (0.5 or 2.0 mug/kg twice daily x 6 weeks) prevented high-fat diet (HFD)-induced increases in body weight, plasma free fatty acids, triglycerides and total cholesterol. Exenatide also prevented HFD-induced deterioration in peripheral and hepatic insulin sensitivity, insulin clearance, glucose tolerance and decreased tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) in fat and skeletal muscles. Interestingly, plasma visfatin levels decreased in exenatide-treated rats, whereas expression and plasma levels of adiponectin increased.


CONCLUSIONS
These results indicate that chronic exenatide treatment enhances insulin sensitivity and protects against high fat-induced insulin resistance.
Li
L
L
Department of Clinical Biochemistry in Chongqing Medical University and The Key Laboratory of Laboratory Medical Diagnostics in the Ministry of Education, Chongqing, China. lingli31@yahoo.com.cn
Yang
G
G
Li
Q
Q
Tan
X
X
Liu
H
H
Tang
Y
Y
Boden
G
G
D052242:Adiponectin / Q000097:blood* / Q000235:genetics; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004041:Dietary Fats / Q000009:adverse effects; D000077270:Exenatide; D005230:Fatty Acids, Nonesterified / Q000097:blood; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood / Q000378:metabolism; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000187:drug effects; D054409:Nicotinamide Phosphoribosyltransferase / Q000097:blood / Q000235:genetics; D010455:Peptides / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000187:drug effects; D014688:Venoms / Q000627:therapeutic use*; D015430:Weight Gain / Q000187:drug effects
D052242:Adiponectin; D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007004:Hypoglycemic Agents; D007328:Insulin; D010455:Peptides; D014688:Venoms; D000077270:Exenatide; D054409:Nicotinamide Phosphoribosyltransferase; D005947:Glucose