The present invention relates to methods for modulating the activity of one or more Vps10p-domain receptors selected from the group consisting of Sortilin, SorLA, SorCS1, SorCS2 and SorCS3, in an animal and methods for preparation of a medicament for the treatment of abnormal plasma lipid concentrations and associated diseases and/or disorders. The modulation is carried out by inhibiting or promoting the binding of ligands to the Vps10p-domain receptor. In vitro and in vivo methods for screening for agents capable of modulation of said Vps10p-domain receptor activity are also provided. The invention furthermore relates to methods of altering expression of said receptors in vivo.