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 the¹⁴C radioactivity of the free fatty acids relative to the³²P 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.