AbstractThe presence of the extracellular calcium-sensing receptor (CaSR) has been demonstrated in numerous cells that are key in the control of serum calcium concentrations, underscoring its relevance in systemic calcium homeostasis. The more recent evidence of its presence in tissues not involved in this function has broadened the spectrum of interest in this protein, now known to regulate diverse cell functions such as proliferation, differentiation, and apoptosis. This study shows the expression of CaSR in human omental adipose tissue, isolated adipocytes, and adipocyte progenitor cells as assessed by RT-PCR and immunoblotting. This is the first report of CaSR being expressed in human adipocytes and adipocyte progenitor cells, opening the possibility to investigate the physiological implications and thus contributing a novel component for adipose tissue biology research.