The cholesterol-lowering effect of guar gum is not the result of a simple diversion of bile acids toward fecal excretion
| Autor: | Christine Guittard, Christian Rémésy, Pierre-Etienne Bost, Marie-Laure Favier, Christian Demigné |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Male
medicine.medical_specialty medicine.drug_class Lipoproteins Guar Biochemistry Galactans Intestinal absorption Excretion Bile Acids and Salts Mannans chemistry.chemical_compound Feces Internal medicine Plant Gums medicine Animals Bile Rats Wistar Cecum Guar gum Bile acid Cholesterol Anticholesteremic Agents Organic Chemistry Body Weight Cell Biology Organ Size Hydrogen-Ion Concentration Dietary Fats Lipids Sterol Rats Endocrinology chemistry Intestinal Absorption Liver Hydroxymethylglutaryl CoA Reductases Lipoprotein |
| Zdroj: | Lipids. 32(9) |
| ISSN: | 0024-4201 |
| Popis: | The effects of partially hydrolyzed, nonviscous, guar gum (PHGG) on cholesterol metabolism and digestive balance have been compared with those of native guar gum (GUAR) in rats adapted to 0.4% cholesterol diets. Both types of guar gum elicited acidic fermentations in the large intestine, but only GUAR effectively lowered plasma cholesterol (P < 0.001), chiefly in the triglyceride-rich lipoprotein fraction. The biliary bile acid excretion was significantly enhanced in rats fed GUAR (P < 0.05), as well as the intestinal and cecal bile acid pool (P < 0.001). In rats fed GUAR and to a lesser extent in those fed PHGG, the fecal excretion of bile acids and neutral sterol was higher than in controls (P < 0.01). The digestive balance (cholesterol intake-steroid excretion) was positive in control rats (+47 mumol/d), whereas it was negative in rats fed GUAR (-20 mumol/d), which could involve a higher rate of endogenous cholesterol synthesis. In rats fed PHGG, the steroid balance remained slightly positive. Liver 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity was very low (22 pmol/min/mg protein), owing to cholesterol supplementation, in control rats or in rats fed PHGG, whereas it was markedly higher (+463%) in rats fed GUAR. In conclusion, even if PHGG does alter some parameters of the enterohepatic cycle of cholesterol and bile acids, its effects are not sufficient to elicit a significant cholesterol-lowering effect. The intestinal (ileal or cecal) reabsorption of bile acids was not reduced, but rather increased, by GUAR; nevertheless the intestinal capacities of reabsorption were overwhelmed by the enlargement of the digestive pool of bile acids. In the present model, induction of HMG-CoA reductase probably takes place in the presence of elevated portal bile acid concentrations. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink