The effect of high-amylose cornstarch on lipid metabolism in OVX rats is affected by fructose feeding

Abstract 

We examined whether the effects of high-amylose cornstarch (HACS) on lipid metabolism in ovariectomized (OVX) rats were affected by high-fructose feeding. Sucrose (482 g/kg diet) was used as fructose source. OVX rats were fed one of the following four diets for 21 days: a sucrose-based or cornstarch-based cholesterol-free diet with or without HACS (150 g/kg diet). Body weight and food intake were increased by sucrose. Plasma total cholesterol and low-density lipoprotein cholesterol concentrations were increased by sucrose and decreased by HACS in cornstarch-fed rats, but not in sucrose-fed rats. Liver total lipids and concentrations of plasma and liver triacylglycerol (TAG) were increased by sucrose, whereas plasma TAG concentration was decreased by HACS, in sucrose-fed rats. However, liver cholesterol concentration was not affected by diet. The amount of cholesterol in small-intestinal contents was increased in sucrose-fed rats, but not in cornstarch-fed rats, but that of bile acids was not affected by diet. Fecal excretions of bile acids and neutral sterols were increased by HACS. The level of sterol-regulatory element-binding protein-1c mRNA was increased by sucrose and decreased by HACS in sucrose-fed rats, but not in cornstarch-fed rats. The level of farnesoid X receptor mRNA was decreased by sucrose and increased by HACS in cornstarch-fed rats, but not in sucrose-fed rats, as was the level of cholesterol 7α-hydroxylase mRNA. These results show that the effect of HACS on hyperlipidemia induced by ovarian hormone deficiency would be affected by the consumption of fructose-rich sweeteners such as sucrose and high-fructose syrup.

Abbreviations: ACAT-1, acyl-coenzyme A:cholesterol acyltransferase 1, ACAT-2, acyl-coenzyme A:cholesterol acyltransferase 2, ApoB, apolipoprotein B, CYP7A1, cholesterol 7α-hydroxylase, CYP8B1, cholesterol 12α-hydroxylase, DF, dietary fiber, FXR, farnesoid X receptor, HDL, high-density lipoprotein, HMG-CoA, 3-hydroxy-3-methylglutaryl coenzyme A, LDL, low-density lipoprotein, LDL-R, low-density lipoprotein receptor, LXR, liver X receptor, MTP, microsomal triglyceride transfer protein, RS, resistant starch, SCFA, short-chain fatty acid, SREBP-1a, sterol-regulatory element-binding protein-1a, SREBP-1c, sterol-regulatory element-binding protein-1c, SREBP-2, sterol-regulatory element-binding protein-2, TAG, triacylglycerol, VLDL, very-low-density lipoprotein.

Keywords: Amylose content, Resistant starch, Ovariectomized rat, Plasma lipids, Bile acids