Increased Plasma Adiponectin and Expression of Hepatic Genes Regulating Lipid Metabolism in HPMC Fed Hamsters

Abstract

Soluble dietary fiber (hydroxypropyl‐methylcellulose, HPMC) is not absorbed by the body but its presence in the intestinal lumen increases fecal fat, sterol, and bile acid excretion which may result in reduced energy availability and indirectly changes in hepatic lipid metabolism. To elucidate the underlying this mechanisms, we measured hepatic expression of genes involved in cholesterol, bile acid, and fatty acid metabolism in male Golden Syrian hamsters fed 39% fat calorie diets containing 5% HPMC or 5% insoluble dietary fiber (microcrystalline cellulose, MCC) for four weeks. Hamsters fed HPMC gained significantly less body weight without changes in food intake and had less plasma and hepatic lipid levels than animals on MCC diet. The expression of hepatic genes related to fatty acid oxidation were up‐regulated and fatty acid synthesis were down‐regulated in hamsters fed diets supplemented with HPMC. HPMC fed animals also had higher levels of plasma adiponectin compared with control animals. Plasma adiponectin may regulate the nuclear receptors, PPAR alpha and SREBP‐1c, resulting in the up‐ or down‐regulation of the downstream genes. In addition, reduced energy availability after HPMC feeding may trigger an increase in plasma adiponectin and decrease in the expression of hepatic lipogenic genes.