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), Journal Name: American Journal of Physiology; (USA) Vol. 259; ISSN 0002-9513; ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ALCOHOLS
ANIMALS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHOLESTEROL
COMPARATIVE EVALUATIONS
ESTERS
GLYCEROL
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INTESTINAL ABSORPTION
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
LABELLED COMPOUNDS
LIPIDS
MAMMALS
METABOLISM
MONOCARBOXYLIC ACIDS
OLEIC ACID
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHOLIPIDS
RATS
RODENTS
STEROIDS
STEROLS
TRACER TECHNIQUES
TRIGLYCERIDES
TRITIUM COMPOUNDS
UPTAKE
VERTEBRATES