Dose-dependent effect of dietary fish-oil (n-3) polyunsaturatedfatty acids on in vivo insulin sensitivity in rat

Abstract

The objective of this study was to assess the effect of dietary fish oil (n-3) polyunsaturated fatty acids (PUFA) on in vivo glucose metabolism and insulin sensitivity of rats. The experiments were carried out on 18 Wistar male rats divided into three groups: control rats given a normal diet containing corn oil, and two experimental groups given 1% or 5% fish oil supplemented diets. Glucose metabolism and insulin sensitivity were assessed by euglycemic clamp technique on anesthetized animals. The results showed: 1) despite the normotensive state of the animals, a significant decrease in blood pressure, especially systolic, and decreased heart rate in both experimental groups; 2) significantly decreased plasma total and LDL cholesterol and nonsignificantly decreased plasma triglycerides; 3) significantly increased bleeding time; 4) normoglycemia and dose-dependent hypoinsulinemia; and 5) significantly increased and dose-dependent in vivo glucose utilization and glucose clearance, significantly increased insulin sensitivity. The above results suggesting that insulin production is suppressed, provide another possible explanation for the beneficial effects of fish oil via modulation of the well-known damaging cardiovascular effects of insulin.