A comparison of absorption of glycerol tristearate and glycerol trioleate by rat small intestine
- Louisiana State University Medical Center, Shreveport (USA)
Generally, fats rich in saturated fatty acids raise serum cholesterol, whereas fats rich in polyunsaturated fatty acids lower it. There appear to be exceptions; e.g., stearic acid (18:0)-rich fats have little or no effect on serum cholesterol concentrations. This apparent lack of cholesterolemic effect of stearic acid-rich fat could be because intestinal absorption of fat is poor or subsequent plasma and/or tissue metabolism of fat is different. To investigate mechanisms involved, we compared intestinal digestion, uptake, and lymphatic transport of glycerol tristearate (TS) and glycerol trioleate (TO, 18:1). Two groups of rats bearing intestinal lymph fistulas were used. TO rats were fed intraduodenally for 8 h at a constant rate a lipid emulsion of 25 mumols/h of TO (labeled with glycerol tri(9,10 (n)-3H)oleate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline. TS rats were fed the same lipid emulsion except that TS replaced TO and the emulsion was labeled with glyceryl (1,3-14C)tristearate. The lymph triglyceride and radioactivity were determined. After infusion, the luminal and mucosal radioactive lipid content was analyzed. The results showed that there was significantly less lipid transported in the lymph of TS rats compared with TO rats. The results also showed a significant decrease in the absorption of TS as compared with TO. This was due in part to poor lipolysis. In addition, the lipid absorbed by the intestine of the TS rats was transported into lymph less efficiently than in TO rats.
- OSTI ID:
- 6422218
- Journal Information:
- American Journal of Physiology; (USA), Vol. 259; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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TRIGLYCERIDES
INTESTINAL ABSORPTION
CARBON 14 COMPOUNDS
CHOLESTEROL
COMPARATIVE EVALUATIONS
GLYCEROL
ISOTOPE DILUTION
METABOLISM
OLEIC ACID
PHOSPHOLIPIDS
RATS
TRITIUM COMPOUNDS
ABSORPTION
ALCOHOLS
ANIMALS
CARBOXYLIC ACIDS
ESTERS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MAMMALS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
RODENTS
STEROIDS
STEROLS
TRACER TECHNIQUES
UPTAKE
VERTEBRATES
550501* - Metabolism- Tracer Techniques