Selenoprotein P is elevated in individuals with obesity, but is not independently associated with insulin resistance

Selenoprotein P (SeP) is secreted primarily by the liver and postulated to cause insulin resistance. The aim of this study was to measure plasma SeP in individuals who are lean (N = 29) or overweight/obese (N = 34), and examine relationships between circulating SeP, SEPP1 (SeP, plasma 1) expression in subcutaneous adipose tissue, and markers of insulin resistance. SeP was higher in individuals who were overweight/obese (P < 0.001), and associated with insulin resistance by HOMA-IR and by clamp, but not independently of BMI. SEPP1 mRNA was correlated negatively with BMI, suggesting there may be tissue specific regulation. This study suggests that obesity, rather than insulin resistance, is central to the increase in SeP.