[High phosphatidylcholine weights compared to lysophosphatidylcholine weights, in micellar intestinal contents, in...

Casein hydrolysat, lactose and lipids (100 mg of fatty acids) were introduced in the stomach of rats by a gastric tube: either pure tri-oleoylglycerol, or phospholipids, or phosphatidylcholines, or the mixture 9/1 to fatty acid weight of tri-oleoylglycerol-phospholipids or phosphatidylcholines. The rats were killed 2 h later. The intraluminal intestinal lipids of the oil and micellar phases were separated after microfiltration (Millipore filters) in preference to the filtration by gel chromatography on polyacrylamide agarose, as an hydrolysis of intraluminal phospholipid occurred after the column elution. 1. After a quantitative recovery of the intestinal lipids (no separation of the oil and micellar phases), a strong hydrolysis of the tri-oleoyglycerol was observed; in opposition, large amounts of intact phospholipids appeared. 2. After isolation of the micellar phases, no triglycerides were recovered, but fatty acids and partial glycerides from the hydrolysed tri-oleoylglycerol and dietary phosphatidylcholines and small quantities of lyso-phosphatidylcholines (hydrolysed forms) were present. 3. After ingestion of the tri-oleoylglycerol as lipid dietary source, the intestinal micellar phases contained endogenous phosphatidylcholines and a few amounts of lysophosphatidylcholines, which had mainly bile origin, since the fatty acid composition of these micellar phosphatidylcholines approached the bile phosphatidylcholine fatty acid composition. The micellar lysophosphatidylcholine masses represented one-fourth of the micellar phosphatidylcholine masses. 4. In these experiments the phosphatidylcholine lysophosphatidylcholine ratio was always high: this means that small quantities of exogenous and endogenous lysophosphatidylcholines appeared in the micellar phases.