Volume 87, Issue 2, February (2002), pp. 157-162 © The Author 2002
doi:10.1079/BJN2001496

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Effect of eicosapentaenoic acid ethyl ester v. oleic acid-rich safflower oil on insulin resistance in type 2 diabetic model rats with hypertriacylglycerolaemia

Asako Minami, Noriko Ishimura, Sadaichi Sakamoto, Eiko Takishita, Kazuaki Mawatari, Kazuko Okada and Yutaka Nakaya*
Department of Nutrition, School of Medicine, The University of Tokushima, Tokushima, Japan

 (Received 12 March 2001–Revised 10 September 2001–Accepted 3 October 2001)

The purpose of the present study was to test whether hyperlipidaemia and insulin resistance in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats can be improved by dietary supplementation with purified eicosapentaenoic acid (EPA) or oleic acid (OA). Male OLETF rats were fed powdered chow (510 g fat/kg) alone (n 8) or chow supplemented with 1·0 g EPA- (n 8) or OA- (n 8) rich oil/kg per d from 5 weeks until 30 weeks of age. An oral glucose tolerance test and hyperinsulinaemic euglycaemic clamp was performed at 25 and 30 weeks of age. EPA supplementation resulted in significantly (P<0.05) reduced plasma lipids, hepatic triacylglycerols, and abdominal fat deposits, and more efficient in vivo glucose disposal compared with OA supplementation and no supplementation. OA supplementation was associated with significantly increased insulin response to oral glucose compared with EPA supplementation and no supplementation. Inverse correlation was noted between glucose uptake and plasma triacylglycerol levels (r -0·86, P<0·001) and abdominal fat volume (r -0·80, P<0·001). The result of oral glucose tolerance test study showed that the rats fed EPA tended to improve glucose intolerance, although this was not statistically significant. Levels of plasma insulin at 60 min after glucose was significantly increased in rats fed OA compared with the other two groups. The results indicate that long-term feeding of EPA might be effective in preventing insulin resistance in diabetes-prone rats, at least in part, due to improving hypertriacylglycerolaemia.

Keywords:
Otsuka Long-Evans Tokushima Fatty rats: Eicosapentaenoic acid: Hypertriacylglycerolaemia: Insulin resistance