Role of biliary lecithin in lymphatic transport of fat.

This study was undertaken to asses the role of luminal lecithin in the lymphatic transportation of fat as chylomicrons. Two doses of fat, the low and high dose, were fed to two different groups of rats, control and bile fistula. At low dose, infusing at 35 mumoles of total fatty acid per hr of a mixture of oleic acid and monoolein, molar ratio 2:1, solubilized in 55 mumoles of sodium taurocholate, there was no difference in the lymphatic output of absorbed fat during steady state (7th and 8th hour) absorption. Infusing at a high dose, 173 mumoles of total fatty acid per hr of a mixture of oleic acid and monoolein, molar ratio 2:1, solubilized in 55 mumoles of sodium taurocholate, the bile fistula rats had lower triglyceride and phospholipid output, with a higher proportion of oleic acid in lymph lecithin than did control rats. These alterations in bile fistula rats returned to normal by addding 10 mumoles per hr of biliary lecithin to the infusate. We conclude that intraluminal biliary lecithin plays a significant role in the translocation of high doses of absorbed fat into lymph and in the amount and type of lecithin synthesized.