Effect of different oil on insulin resistance and gluconeogenesis in rats

Objective: To compare the effects of different oil on insulin resistance and gluconeogenesis in SD rats.Methods: Male SD rats were divided into four groups ( n = 7) .Rats in the control group were fed normal diet and the high fat diet groups were fed with diet containing different oil ( lard, olive, and camellia seeds oil) .Rats were fed for 17 weeks.Oral glucose tolerance test ( OGTT) and insulin tolerance test ( ITT) were performed before sacrificed. The artery blood samples were collected after anesthesia, then serum were separarted to detect the levels of fasting plasma glucose ( FPG) , fasting serum insulin ( FINS) and adiponectin.The mRNA expression of phosphoenolpyruvate carboxykinas ( PEPCK) and glucose-6-phosphatase ( G6P) related to gluconeogenesis in liver, were analyzed by real time PCR.Results: Rats in each oil-fed group showed different levels of insulin resistance.Lard-fed rats led to the significantly increased in levels of FPG, FINS and HOMA-IR ( p < 0.05) , impaired OGTT and ITT performance. The level of serum adiponectin was decreased in lard-fed rats compared with others ( p < 0.05) . The expression of gluconeogenesis-related genes ( PEPCK and G6Pase) in all oil-fed rats were higher than those in control group ( p < 0.05) . The mRNA expression in lard-fed rats were significantly higher than other groups ( p < 0.05) . Olive oil and camellia seeds oil-fed rats showed little difference compared with the normal group, but there was statistical significance ( p <0.05) .Conclusion: Lard riched in saturated fatty acids ( SFA) may increase the risk of IR.The olive and camellia seeds oil, which have great amount of unsaturated fatty acids ( UFA) , induced significantly lower degree of IR than lard ( p < 0.05) .Camellia seed oil as a characteristic oil in China, can be used as a high quality oil.