Uptake of Chylomicron Lipid by Rat Liver Parenchymal Cells in vivo

Abstract

THERE are two theories about the uptake of chylomicron triglyceride by the liver. The widely held view that chylomicrons are removed intact from the circulation^1–3 has been challenged by Felts and Mayes⁴. They propose that the triglycerides are not taken up directly by the liver but are hydrolysed elsewhere by lipoprotein lipase, the resulting non-esterified fatty acids (NEFA) being taken up by the liver cells. In vivo evidence that intact chylomicrons are removed by the liver has been presented earlier⁵ but was open to two objections^4,6. First, heparin was used as an anticoagulant in the collection of the chylomicrons and sufficient could have remained after washing to stimulate lipoprotein lipase activity in the circulation. Second, studies on whole liver tissue may not give a true picture of events occurring in the parenchymal cells themselves, since trapping of chylomicrons in the tissue spaces does occur both in vivo⁷ and in perfusion experiments⁶.