EFFECT OF DIFFERENT DIETARY FAT ON GLUCOSE TOLERANCE AND INSULIN SENSITIVITY / 营养学报

ABSTRACT

Objective: To investigate the effects of different dietary fat on insulin sensitivity and glucose tolerance in rats. Methods: Fifty adult male Sprague-Dawley rats were randomly assigned to five groups and fed on basal diet (low fat diet) and four test diets containing 30.4% fat of total energy as lard, perilla oil, sunflower oil or olive oil respectively for 6 w. An oral glucose tolerance test (OGTT) was performed and blood samples were taken for measurement of serum insulin, triglyceride (TG) and total cholesterol (TC) level. Insulin sensitivity index (ISI) was calculated and epididymal fat pad was weighed. Results: In comparison with rats fed low fat, rats fed lard had a low ISI and a high serum glucose level 120 min after glucose load. The ISI in groups of sunflower oil and olive oil was markedly higher than in lard group, whereas serum glucose at 120 min was significantly lower. Serum glucose and insulin level both at 0 min and 120 min were significantly lower and ISI was higher in perilla oil group than that in lard group. Moreover, rats fed perilla oil had a low fasting glucose and a higher ISI compared with rats fed sunflower oil, olive oil and low fat respectively. Serum TC and TG were significantly lower in rats fed perilla oil than in rats fed low fat and lard respectively. Relative epididymal fat pad weight was lower in rats fed perilla oil than in rats fed lard. Conclusion: Perilla oil is effective in increasing insulin sensitivity and improving glucose metabolism in rats, and the effects of sunflower oil and olive oil are between that of perilla oil and lard. The hypoglycemic effect of perilla oil might be mediated, at least in part by reducing triglyceride level and body fat accumulation.