Observations concerning the production and excretion of cholesterol in mammals. III. The source of excess plasma cholesterol after ligation of the bile duct.

The rise in plasma cholesterol, occurring after ligation of the common bile duct of most mammals, is recognized. Some observers (l-3) believe this cholesterol to be formed in the liver; others (4) think that the liver may excrete cholesterol formed elsewhere. A study of plasma cholesterol after hepatectomy would decide this question, for a rise similar to that following bile duct ligation should occur if the liver is merely an excretory organ, while no rise could occur if the liver acts primarily as a source of cholesterol. This crucial experiment has not been reported because the survival time after hepatectomy is usually less than the time required for the accumulation of plasma cholesterol in control animals subjected solely to ligation of the bile duct. The liverless dog, for instance, rarely survives more than 24 hours, but 1 or 2 weeks are required (5) for a consistent rise, in plasma cholesterol to become evident after duct ligation. Results of work with dogs are therefore inconclusive (6). We have found (7) that the rat accumulates plasma cholesterol after duct ligation sufficiently rapidly to allow observation of the results of procedures which might prove fatal in other species before a significant change t.ook place. These results indicate that the source of the cholesterol increment in the plasma after bile duct ligation is the liver.