Dietary supplementation with alpha-amylase inhibitor wheat albumin to high-fat diet-induced insulin-resistant rats is associated with increased expression of genes related to fatty acid synthesis in adipose tissue.

It is well-known that insulin resistance induces lipid abnormalities by decreasing insulin actions in adipose tissue. This study examined the effects of inhibiting postprandial hyperglycemia/hyperinsulinemia, using the alpha-amylase inhibitor wheat albumin (WA), on the expression of genes related to fatty acid metabolism in the adipose tissue of high-fat diet-induced insulin-resistant rats. Postprandial glucose and insulin levels were significantly lower after oral starch loading with WA than with inactivated WA in insulin-resistant rats. In addition, the increases in the plasma triacylglycerol and insulin levels by feeding insulin-resistant rats a control diet were inhibited by WA supplementation. Supplementation with WA increased the mRNA levels of not only fatty acid synthase (FAS) and acyl-CoA carboxylase (ACC) but also their transcriptional factors such as carbohydrate response element-binding protein (ChREBP) and sterol regulatory element binding protein (SREBP)1 in the mesenteric adipose tissue of the insulin-resistant rats. In addition, supplementation with WA tended to increase the protein expression levels of FAS and ACCs. These results suggest that reductions in the plasma triacylglycerol and insulin levels by inhibiting hyperglycemia/hyperinsulinemia with the alpha-amylase inhibitor WA in high-fat diet-induced insulin-resistant rats are associated with increased expression of genes related to fatty acid synthesis and their transcriptional factors in adipose tissue.