Griglio S, Sultan F, Lagrange D
Laboratoire de Physiopathologie de la Nutrition, Unité INSERM U 177, Paris, France.
Diabete Metab. 1992;18(1 Pt 2):150-5.
Before being taken up by the liver, chylomicrons are hydrolyzed successively by two lipases. The first one is the lipoprotein lipase which hydrolyzes mainly chylomicron triacylglycerols and gives rise to remnant particles. The latters will be further hydrolyzed by the hepatic lipase which exerts mainly a phospholipase A1-like activity on these particles. Chylomicrons as well as remnants, incubated with hepatic lipase in vitro, lose up to 47% of their phospholipids while triacylglycerols are less or even not hydrolyzed at all. A decrease in phosphatidylcholine (-30% and -34%) and an increase in lysophosphatidylcholine (+260% and +316%) are the main modifications measured in chylomicrons and in their remnants respectively, after hepatic lipase action. From several date (Borensztajn's work and ours), it arises that phospholipolysis of chylomicrons and of chylomicron remnants, is the obligatory metabolic step before these particles are taken up and degraded by the liver.
在被肝脏摄取之前，乳糜微粒会先后被两种脂肪酶水解。第一种是脂蛋白脂肪酶，它主要水解乳糜微粒的三酰甘油，产生残余颗粒。后者将被肝脂肪酶进一步水解，肝脂肪酶对这些颗粒主要发挥类似磷脂酶A1的活性。在体外与肝脂肪酶一起孵育时，乳糜微粒及其残余颗粒会损失高达47%的磷脂，而三酰甘油则很少或根本不被水解。在肝脂肪酶作用后，分别在乳糜微粒及其残余颗粒中测得的主要变化是磷脂酰胆碱减少（分别为-30%和-34%）和溶血磷脂酰胆碱增加（分别为+260%和+316%）。从多个数据（博伦施泰因的研究和我们的研究）来看，乳糜微粒及其残余颗粒的磷脂分解是这些颗粒被肝脏摄取和降解之前必不可少的代谢步骤。
