Selenoprotein P (SelP) is an extracellular glycoprotein that carries approximately 40% of plasma selenium (Akesson et al. 1994). SelP is unique among the selenoproteins in that it can possess up to ten selenocysteine residues in mammals (Burk & Hill 2005). SelP primarily functions in selenium distribution (Hill et al. 2003; Renko et al. 2008), with knockout mice displaying altered selenium distribution, particularly to the testes and brain (Hill et al. 2003; Burk et al. 2006). The majority of SelP is derived from hepatic sources, however; the mRNA can be detected in almost all tissues, with appreciable concentrations observed in the kidney, heart, lung, brain, skeletal muscle, and testis (Burk & Hill 2005)
