Participation des acides gras du sang et de la bile a la formation des lipides endogenes de la lymphe chez le rat qui ingere un repas contenant des graisses

Abstract

Two kinds of experiments were performed on fat fed rats with cannulated thoracic ducts. Experiment I. The animals received potassium [9,10- 3H 2]oleate by intravenous injection. For some of them, radioactive bile fistula was performed, but in order to establish a good fat absorption, non-radioactive bile collected from normal rats was introduced into the duodenum by a re-entrant bile cannula. In these rats, a decrease of only 25% of radioactivity in lipids of thoracic lymph can be estimated by comparison to the data obtained on rats without bile fistula. Experiment II. Small amounts of radioactive bile were injected into the duodenum of rats. After this infusion, the recovered activity in the lymph lipids during a collection time of 17 h was only 10% of the radioactive bile lipids introduced. In experiments having a short duration (1 h), a large amount of the [ 3H]oleic acid (70% found in bile phospholipids) went into the portal blood instead of the thoracic lymph, and about 50% of the [ 3H]oleic acid was present in portal blood phospholipids. It seems that bile phospholipids have not the same way of absorption as dietary phospholipids. The fatty acid pattern of endogenous lymph lipids is nearer to that of plasma free fatty acids than to that of bile fatty acids. In fat fed rats, blood fatty acids are much more important as a source of endogenous lipids in the thoracic lymph and particularly in chylomicrons triglycerides than are bile fatty acids.