LPL gene expression and enzymatic levels increase following differentiation of pre-adipocytes. 3T3-L1 cells were treated with or without adipocyte induction reagents as described in Methods. (A) Total RNA was extracted from cells and LPL mRNA levels were measured by qRT-PCR using the Comparative CT method. Inset, specific amplification of leptin sequence (213 bp) was done by straight reverse transcriptase-PCR to confirm differentiation of pre-adipocytes. Amplification of β-actin sequence (287 bp) was performed as a loading control. (B) Cells were incubated with heparin (200 μg/ml) to release surface associated LPL. The heparin releasable fraction was then incubated with p-nitrophenyl butyrate (1 mM final concentration) for 10 min and absorbance was measured at 405 nm.