Prostaglandin E1 increases binding of 123I-low-density lipoprotein to the human liver in vivo

Abstract

Previous in vitro radioligand binding data have shown that prostaglandin E1 (PGE1) increases the number and the binding affinity of low-density lipoprotein (LDL) receptors of the human liver. Experimental data in normo- and hypercholesterolaemic rabbits have confirmed these findings, showing a significant increase in LDL-binding to the liver in vivo after prolonged PGE1 therapy. METHODS. This study aimed to confirm the experimental and animal data in human in vivo. 123I-LDL binding to the liver was quantified in vivo in patients suffering from peripheral vascular disease, seven of them with heterozygous familial hypercholesterolaemia (HC) and five with normal total plasma cholesterol, after PGE1 administration (5 ng.kg-1.min-1; 6 h daily for 5 days/week for 5 weeks). LDL uptake by the liver was quantified by single photon emission computer tomography (SPECT). RESULTS. The amount of LDL trapped by the liver in normocholesterolaemics (45.6%) was significantly higher than in hypercholesterolaemics (22.0%). PGE1 induced an increase in liver LDL binding, which was more pronounced in HC (+38.2%) than in normocholesterolaemic patients (+8.11%).