Rice protein regulates HDL metabolism-related gene expression and enzyme activity in adult rats

To elucidate whether rice protein possess a vital function in regulating high density lipoprotein (HDL) metabolism, the effects of rice protein (RP) on HDL metabolism-related gene expressions and enzyme activities were investigated in adult rats. Compared with casein, lipid contents in plasma and liver were effectively reduced by RP-feeding, accompanying significant increased ratio of HDL to cholesterol or triglyceride. RP increased mRNA levels of lecithin-cholesterol acyltransferase, adenosine triphosphate-binding cassette transporter A1, scavenger receptor class B type I and liver X receptor α, as compared to casein. Hepatic activities of lipoprotein lipase and hepatic lipase were significantly stimulated by RP, whereas no significant difference of plasma lecithin-cholesterol acyltransferase activity was found in RP with respect to casein. Results demonstrated that rice protein could effectively regulate HDL metabolism through modifying the HDL metabolism-related gene expression levels and lipolytic enzyme activities, which involved with a hypocholesterolemic action during the adult period.