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Research Article Free access | 10.1172/JCI105587
Hospital of the Rockefeller University, New York, N. Y.
†Commonwealth Fund Fellow. Present address: University of Western Australia, Nedlands, Australia.
‡Address requests for reprints to Dr. Alan F. Hofmann, Gastroenterology Unit, Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901.
§Postdoctoral trainee, Dept. of Medicine, Cornell University Medical College, under U. S. Public Health Service grant TI AM 5430, National Institute of Arthritis and Metabolic Diseases, and fellow of the John A. Hartford Foundation. Present address: Tel-Hashomer Government Hospital, Tel-Aviv, Israel.
*Submitted for publication October 3, 1966; accepted February 2, 1967.
This study was supported by U. S. Public Health Service grant HE-06222, National Heart Institute, to Professor E. H. Athens, Jr., and in part by U. S. Public Health Service grant FR-00102 from the General Clinical Research Centers Branch of the Division of Research Facilities and Resources.
Presented in part before the Gastroenterology Sectional Meeting of the American Federation for Clinical Research on May 1, 1966, and published in abstract form (1).
Find articles by Simmonds, W. in: JCI | PubMed | Google Scholar
Hospital of the Rockefeller University, New York, N. Y.
†Commonwealth Fund Fellow. Present address: University of Western Australia, Nedlands, Australia.
‡Address requests for reprints to Dr. Alan F. Hofmann, Gastroenterology Unit, Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901.
§Postdoctoral trainee, Dept. of Medicine, Cornell University Medical College, under U. S. Public Health Service grant TI AM 5430, National Institute of Arthritis and Metabolic Diseases, and fellow of the John A. Hartford Foundation. Present address: Tel-Hashomer Government Hospital, Tel-Aviv, Israel.
*Submitted for publication October 3, 1966; accepted February 2, 1967.
This study was supported by U. S. Public Health Service grant HE-06222, National Heart Institute, to Professor E. H. Athens, Jr., and in part by U. S. Public Health Service grant FR-00102 from the General Clinical Research Centers Branch of the Division of Research Facilities and Resources.
Presented in part before the Gastroenterology Sectional Meeting of the American Federation for Clinical Research on May 1, 1966, and published in abstract form (1).
Find articles by Hofmann, A. in: JCI | PubMed | Google Scholar
Hospital of the Rockefeller University, New York, N. Y.
†Commonwealth Fund Fellow. Present address: University of Western Australia, Nedlands, Australia.
‡Address requests for reprints to Dr. Alan F. Hofmann, Gastroenterology Unit, Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901.
§Postdoctoral trainee, Dept. of Medicine, Cornell University Medical College, under U. S. Public Health Service grant TI AM 5430, National Institute of Arthritis and Metabolic Diseases, and fellow of the John A. Hartford Foundation. Present address: Tel-Hashomer Government Hospital, Tel-Aviv, Israel.
*Submitted for publication October 3, 1966; accepted February 2, 1967.
This study was supported by U. S. Public Health Service grant HE-06222, National Heart Institute, to Professor E. H. Athens, Jr., and in part by U. S. Public Health Service grant FR-00102 from the General Clinical Research Centers Branch of the Division of Research Facilities and Resources.
Presented in part before the Gastroenterology Sectional Meeting of the American Federation for Clinical Research on May 1, 1966, and published in abstract form (1).
Find articles by Theodor, E. in: JCI | PubMed | Google Scholar
Published May 1, 1967 - More info
The absorption of cholesterol has been studied in man by perfusing the upper jejunum with a micellar solution of bile salt, 1-monoglyceride, and cholesterol-14C, with a triple lumen tube with collection sites 50 cm apart. The absorption of micellar components between the collection sites was calculated from their concentration changes relative to those of the watersoluble marker, polyethylene glycol. Control experiments were performed with cholesterol-free perfusions of saline or bile salt-monoglyceride solutions. Steady state conditions were obtained.
Each of the components of the micelle was absorbed to a different extent during passage through the test segment of jejunum. Bile salt was not absorbed (mean, -3%), but micellar monoglyceride was rapidly hydrolyzed and absorbed almost completely (mean, 98%). Cholesterol radioactivity was absorbed to an intermediate extent (mean, 73%), and the absorption of chemically determined cholesterol (mean, 46%) indicated that much of the disappearance of radioactivity represented true absorption and not simple exchange.
The specific activity of the perfused cholesterol fell during passage through the loop. This fall was interpreted as signifying the continuous addition of nonradioactive endogenous cholesterol by the test segment. However, the decrease in specific activity may also be considered to signify exchange, in that nonradioactive molecules entered the lumen as radioactive molecules were absorbed. Plant sterols appeared in the intestinal contents during the perfusion and must have been contributed by the perfused segment.
The perfusate and samples taken from the upper and lower collection sites were examined by ultracentrifugation to define the physical state of cholesterol. It was found that cholesterol in the perfusate or upper collection site samples did not sediment, but that 23% of the cholesterol in the lower collection site samples was sedimentable (mean of three experiments); bile salt, as control, was not sedimentable. Solubility experiments in model systems showed that cholesterol possessed low solubility in bile salt solution; its solubility increased markedly and in linear proportion to the amount of fatty acid or monoglyceride or both that was added to the bile salt solution. These findings suggest that polar lipid such as fatty acid or monoglyceride as well as bile salt is essential for normal micellar solubilization of cholesterol in intestinal content. They suggest the necessity of considering an insoluble sedimentable phase of particulate sterol in intestinal content as well as an oil and micellar phase for a complete description of sterol absorption.
The marked difference in the rates of absorption of individual micellar components suggests that micellar lipid is not absorbed as an intact aggregate and is consistent with the view that polar lipid such as fatty acid is absorbed in molecular form by diffusion from a micellar solution. The experiments confirm previous findings demonstrating that fat absorption without bile salt absorption occurs in the upper small intestine in man.
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