PRLr and PRL expression in THP-1 monocytes activated with LPS using Western blot. THP-1 monocytes stimulated with LPS 1 μg/ml were harvested at different times and two independent Western blot experiments were performed and analyzed using densitometry analysis (graph): A, PRLr; and B, PRL. As positive controls of PRLr isoforms the total protein extract from breast cancer cell line (MCF-7), showing short, intermediate and long isoforms, was included. A positive control for human recombinant PRL (hrPRL) showing 50, 23 and 16 kDa forms was included. Anendogenous control of β-Actin showing 43 kDa was revealed. Data are expressed as mean ± SD, and significance vs. untreated (UT) control is defined as: p<0.05*; p<0.01**; and between 1 versus later hours p<0.05†; p<0.01††.