RELATIONSHIP OF PHOSPHATIDYLCHOLINE TO HYDROPHOBIC SURFACTANT ON RAT INTESTINAL CHYLOMICRON SECRETION

Hydrophobic surfactants such as Poloxalene inhibit triglyceride secret ion into lymph by enterocytes. The inhibitory effect of these agents o n triglyceride secretion is reversed when lipid presented for absorpti on is exclusively in the form of phosphatidylcholine (PC) and not trig lyceride. The present investigation performed in conscious mesenteric lymph fistula rats was designed to determine whether various mixtures of triglyceride and PC given intraduodenally with Poloxalene would als o reverse the inhibitory effect of Poloxalene on triglyceride secretio n into lymph. A 50-50 mixture of triolein (TO) and PC resulted in norm al triglyceride secretion into lymph. However, when the mixture of lip ids was 75-25, TO to PC, results for triglyceride recovery in lymph we re considerably reduced. The transport rate for triglyceride into lymp h was not as depressed, however, as observed for Poloxalene treated ra ts given lipid for absorption basically in the triglyceride form. Subs titution of phosphatidylethanolamine for PC had no beneficial effect o n triglyceride secretion in Poloxalene treated rats. It is concluded t hat PC can reverse the inhibitory effect of Poloxalene on triglyceride secretion into lymph even when considerable amounts of triglyceride a long with PC are presented for absorption.