Orexin A Correlated with IGF-1 and Lipid Metabolism in Obesity Rat with Insulin Resistance

Objective To investigate the correlation of orexin A( OXA) with insulin- like growth factor 1( IGF- 1) in besity rat with insulin resistance induced by high- fat diet. Methods Male Sprague- Dawley rats model with insulin resistance induced by high- fat diet was verified by euglycemic insulin clamp technique to determine the insulin resistance.The rats were treated with OXA( 0 to 10- 6M) by hypodermic injection. The serum levels of OXA and IGF- 1 in SD rat were detected by luminescent immunoassay enzymic method. Results After 6 weeks high- fat diet,serum insulin,total cholesterol( TC),triglyeride( TG) and low density lipoprotein( LDL- C) increased significantly in obesity rats with insulin resistance( P 0. 05),the GIR60- 120in obesity rats was decreased significantly,compared with normal rats. After treated with OXA( 10- 8M,10- 7M and 10- 6M),the levels of serum IGF- 1 decreased 25. 0%,43. 5% and 55. 6% in normal rats,respectively,decreased 11. 3%,17. 7% and 27. 4% in obesity rats,respectively. The correlation coefficient between OXA and serum IGF- 1,high density lipoprotein( HDL- C) in insulin resistance rats were- 0. 342 and- 0. 226,P 0. 05.The correlation coefficient between OXA and serum insulin,TC,TG,LDL- C in insulin resistance rats were 0. 303,0. 388,0. 255,0. 253,P 0. 05. Conclusions High- fat diet could induce insulin- resistance and obesity in SD rat. OXA correlated with IGF- 1 in insulin- resistance in SD rat. That OXA down- regulated serum IGF- 1 would involve in insulin- resistance in high- fat diet induced obesity rat.