Comparison of hydrophobic surfactant and cholestyramine on lipid and sterol balance in the rat

Abstract

The effects of dietary supplement with hydrophobic surfactant, Pluronic L-81, on sterol and lipid metabolism in rats consuming a high-fat high-cholesterol diet was determined. Results were compared both to rats on the high-fat high-cholesterol diet alone and to other rats on a similar diet supplemented with cholestyramine. All treatment programs were well tolerated. Pluronic L-81 therapy produced reductions of plasma and hepatic cholesterol levels compared to rats on the diet alone. Additionally, plasma triglycerides were reduced. These changes were associated with relatively high fecal outputs of neutral steroids but acidic steroid excretion was less than observed for rats on diet alone. No malabsorption of neutral lipid was observed for detergent-treated rats. Cholestyramine was also effective in limiting hepatic cholesterol accumulation. Fecal losses of both neutral and acidic steroids were greater in this group compared to rats on diet alone. This was associated with a marked increase of hepatic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity in the cholestyramine-treated group. Both types of treatment limit cholesterol accumulation in rats on a high cholesterol diet. Pluronic L-81 treatment, however, does not significantly increase endogenous cholesterol synthesis while it is greatly increased in response to cholestyramine as reflected by hepatic activities of HMG-CoA reductase.