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S J Robins

Publications and source records attributed to S J Robins.

61 records · Page 4Linked to original sources

Billiary lecithin secretion. II. Effects of dietary choline and biliary lecithin synthesis.

Choline which is absorbed from the intestine isne produced no change in bile salt pool size or secretion rate. However, with each increment in dietary choline, biliary lecithin as well as cholesterol secretion rates were significantly increased. The results demonstrate that although bile salt is required for biliary lecithin secretion, the magnitude of secretion is principally dependent upon the extent of biliary lecithin synthesis, which in turn may be regulated by the amount of dietary choline. Results further indicate that biliary cholesterol secretion is more closely linked to lecithin than to bile salt secretion. These findings would therefore suggest that lecithin secretion might be independently manipulated when bile salt is deficient to achieve enhanced biliary cholesterol transport.

Animal Nutritional Physiological Phenomena↗

Recirculation and reutilization of micellar bile lecithin.

Bile lecithins, solubilized in micellar bile salt and radiolabeled in the 1-acyl fatty acid, phosphorus, and choline positions, were infused in the small bowel of fasted rats. Absorption of each label was virtually complete after 24 h. However, these lecithins were extensively hydrolyzed in the bowel lumen as well as after absorption, and neither the fatty acid nor phosphorus was significantly retained in the enterohepatic circulation or reutilized for biliary lecithin synthesis. In contrast, while choline was also dissociated from absorbed lecithin, choline was instead retained in the liver, reincorporated into newly synthesized hepatic lecithin, and sercreted in biliary lecithin in 10-fold greater amounts than either the fatty acid or phosphorus. However, the extent of choline incorporation into bile lecithin was limited and was not further increased when free choline was directly injected into the portal vein. The data therefore suggest that although only choline of absorbed lecithin is retained in the enterohepatic circulation and preserved for new biliary lecithin synthesis, exogenous choline utilization is regulated by the size of the available hepatic pool.

Animals↗