Hydrolysis of biliary phospholipids in the upper small intestine of the chick.

Chick endogenous phospholipids were doubly labeled by an intravenous injection of [32P] phosphate and [1-14C] oleic acid, and the free fatty acid and phospholipid fraction of gall bladder bile and in contents of upper small intestine were analyzed 4 days later. There was evidence of hydrolysis of biliary phosphatidylcholine to lysophosphatidylcholine in the duodenum and jejunum, but this did not account for the pronounced increase in the 14C radioactivity of the free fatty acids relative to the 32P phospholipid radioactivity between bile and upper intestinal segments. It is suggested that phosphatidylcholine is largely absorbed in the duodenum of the chick while the remainder is progressively hydrolyzed and absorbed.