title: Hepatic lipase activity is decreased in Japanese patients with type III hyperlipoproteinemia.
abstract: BACKGROUND
  Type III hyperlipoproteinemia (HLP), a disorder associated with a high incidence of premature cardiovascular diseases, is characterized by the accumulation of remnant lipoproteins in the plasma. The primary genetic defect in patients with type III HLP is the presence of apolipoprotein E2 (apoE2), an isoform of apoE, and accumulation of remnant lipoproteins in the plasma has been thought to be attributable to the presence of apoE2, which bind poorly to low density lipoprotein receptors, resulting in defective remnant lipoprotein clearance. On the other hand, the activity of hepatic lipase (HL), the enzyme that plays a pivotal role in the removal of remnant lipoproteins, in type III HLP has not been investigated.
  
  
  METHODS
  We examined post-heparin plasma lipoprotein lipase (LPL) and HL activities in 7 patients with type III HLP. The activities of HL and LPL in post-heparin plasma were measured separately by an immunochemical method using antiserum specifically directed against HL.
  
  
  RESULTS
  The post-heparin plasma HL activity was significantly reduced, while the LPL activity was normal.
  
  
  CONCLUSIONS
  Reduced HL activity may account, at least in part, for the accumulation of remnant lipoproteins in the plasma, a characteristic feature of type III HLP.
authors.affiliation: Okinaka Memorial Institute for Medical Research, 2-2-2 Toranomon, Minato-ku, Tokyo 105-8470, Japan. tomurase@toranomon.gr.jp
authors.forename: Toshio
authors.initials: T
authors.lastname: Murase
authors.forename: Tetsu
authors.initials: T
authors.lastname: Ebara
authors.forename: Minoru
authors.initials: M
authors.lastname: Okubo
mesh_terms: D000328:Adult; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D006952:Hyperlipoproteinemia Type III / Q000097:blood / Q000378:metabolism*; D008049:Lipase / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
chemical_list: C504173:LIPC protein, human; D008049:Lipase