Stimulation of lipolysis enhances the rate of cholesterol efflux to HDL in adipocytes

Mol Cell Biochem. 2007 Aug;302(1-2):241-8. doi: 10.1007/s11010-007-9447-0. Epub 2007 Mar 28.


Adipose tissue constitutes a major location for cholesterol storage and, as such, it may play a role in the regulation of circulating cholesterol levels. A possible metabolic link between the lipolytic activity of adipocytes and their ability to release cholesterol to reconstituted human high density lipoprotein, HDL, was investigated in 3T3-L1 adipocytes. In the presence of HDL, composed of human apoA-I and phosphatidylcholine, adipocytes release cholesterol in a lipoprotein-dose and time dependent fashion. beta-adrenergic activation of the lipolysis promotes a 22% increase in the extent of cholesterol efflux to reconstituted discoidal HDL particles. Activation of lipolysis promotes a rapid decrease in the cholesterol content of the plasma membrane and a concomitant increase in lipid droplet cholesterol. This change is independent of the presence of HDL. Activation of the lipolysis does not affect the levels of ABCA1 and SR-BI. Therefore, the enhancement of cholesterol efflux is not due to the level of plasma membrane cholesterol, or to the levels of the cholesterol transporters ABCA1 and scavenger receptor SR-BI. Brefeldin A did not affect the rate of cholesterol efflux under basal lipolytic conditions, but it abolished the lipolysis-dependent enhancement of cholesterol efflux to HDL. This study suggests that activation of lipolysis is accompanied by an increase in BFA-sensitive vesicular transport that in turn enhances cholesterol efflux to HDL. The study supports a metabolic link between the lipolytic activity of adipocytes and the rate of cellular cholesterol efflux to HDL.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • ATP Binding Cassette Transporter 1
  • ATP-Binding Cassette Transporters / metabolism
  • Adipocytes / drug effects
  • Adipocytes / metabolism*
  • Animals
  • Brefeldin A / pharmacology
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cholesterol / metabolism*
  • Humans
  • Lipolysis* / drug effects
  • Lipoproteins, HDL / metabolism*
  • Mice
  • Scavenger Receptors, Class B / metabolism


  • ABCA1 protein, human
  • ATP Binding Cassette Transporter 1
  • ATP-Binding Cassette Transporters
  • Lipoproteins, HDL
  • Scavenger Receptors, Class B
  • Brefeldin A
  • Cholesterol