Inhibition of LPL gene expression in adipocytes causes a corresponding reduction in cell surface, HSPG-associated LPL activity and intracellular lipid accumulation. 3T3-L1 cells were transfected with LPL-specific siRNA, followed by incubation with adipocyte induction reagents for 5 days. (A) Total RNA was isolated from cells and subjected to qRT-PCR analysis to determine relative LPL and leptin mRNA expression levels in siRNA treated and non-treated control cells. (B) Heparin-releasable LPL enzymatic activity was measured in siRNA treated and non-treated control cells as described in Fig. 1. (C) Intracellular lipid droplet formation was quantified by measuring adipocyte-associated Nile Red using fluorometry.