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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, METHODS, RESULTS. Meshes: Adult, Apolipoprotein B-48, Apolipoproteins B, Cholesterol, Cholesterol, Dietary, Chylomicrons, Deuterium, Gas Chromatography-Mass Spectrometry, Humans, Intestinal Absorption, Intestine, Small, Lipoproteins, HDL, Lipoproteins, LDL, Male, Postprandial Period, Reference Values, Triglycerides.
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Is dietary cholesterol secreted in intestinally derived chylomicrons during several subsequent postprandial phases in healthy humans? Context: The process of intestinal absorption and chylomicron resecretion of dietary cholesterol in humans is poorly understood. The present study aimed to test the hypothesis that dietary cholesterol ingested during a given meal is resecreted into chylomicrons (and plasma) during several subsequent postprandial periods. Seven healthy subjects ingested 3 comparable mixed test meals (at 0, 8, and 24 h) containing a given amount of fat (49 g) and cholesterol (157 mg); blood samples were taken 3 and 6 h after each test meal and 48 and 72 h after the beginning of the experiment. Heptadeuterated dietary cholesterol was present in the first test meal only, enabling its specific determination with use of gas chromatography-mass spectrometry. Chylomicrons, LDL, and HDL were isolated and lipids were quantified. In apolipoprotein B-48-containing chylomicrons, deuterated cholesterol concentrations were moderate after the first meal (1.3 x 10(-4) mmol/L), reached a maximum after the second meal (2.4 x 10(-4) mmol/L), and were still elevated after the third meal (1.7 x 10(-4) mmol/L). In plasma, LDL and HDL cholesterol enrichment in deuterated cholesterol was lower than in chylomicrons and plateaued after 24--48 h. Estimates of newly secreted exogenous deuterated cholesterol in chylomicrons indicate that 30.7%, 55.2%, and 14.1% of the total was secreted after the first, second, and third meals, respectively.
assistant
Ingested dietary cholesterol is secreted by the small intestine in chylomicrons into the circulation during > or =3 subsequent postprandial periods in healthy humans. This likely results from a complex multistep intestinal processing of cholesterol with dietary fat as a driving force. Final Decision: yes