Observations Concerning the Production and Excretion of Cholesterol in Mammals

Publisher Website
Google Scholar
Abstract
Five rats were colectomized and the 72 hr. fecal contents compared with similar contents and fecal collection from 10 normal controls. Each of the rats received 3 cc. of olive oil by stomach tube. Rats without colons excreted an avg. of 38.6 mg. of total sterol, normal rats excreted 46.2 mg. The abdominal segment of the thoracic lymph duct was cannulated in 3 other colectomized rats receiving olive oil and the 24 hr. lymph collection compared with that from 10 non-colectomized controls. The lymph vol. was 15.2 cc. in the exptL group and 39.2 cc. in the controls. The total cholesterol averaged 4.7 mg./24 hr. collection in the exptl. group and 9.6 mg. in the controls. When colectomized, thoracic duct cannulated rats were given 100 mg. of cholesterol in olive oil, 6 rats averaged 21.5 mg. of cholesterol/24 hr. lymph collection, while the lymph from 10 controls retaining an intact gastrointestinal tract averaged 27.1 mg. In another expt. bile was diverted to a newly formed entrance into the ascending portion of the colon, preventing significant cholesterol absorption in the small intestine. The cholesterol in the 24 hr. lymph collection from 8 such animals fed 100 mg. of cholesterol averaged 5.9 mg. When 2 rats were subjected to an operation in which the bile was diverted to the stomach, the avg. cholesterol absorption in the lymph was 26 mg. When bile was diverted to the distal half of the small intestine, 4 rats averaged 19.8 mg. of cholesterol in the lymph during the 24 hrs. following cholesterol feeding. When a ligature was placed about the middle of the small intestine of 8 rats, preventing entrance of orally administered cholesterol or olive oil into the distal half, the avg. cholesterol found in 24-hr. lymph was 4.6 mg. When the same amt of cholesterol was introduced directly into the distal half of the ligated small intestine of 4 rats, an avg. of 16.4 mg. of cholesterol was found in the lymph. Histological studies on normal rats fed cholesterol show no Sudan staining of the upper third of the small intestine, moderate staining of the middle third, and intense staining of the lower third. No staining was found in the colon. In the rat most of the cholesterol excreted into the intestinal contents is discharged by the small intestine, and the distal half of the small intestine is the only portion of the gastrointestinal tract capable of absorbing exogenously derived cholesterol.