Selenoprotein P (Sepp1) contains most of the selenium in blood plasma, and it is utilized by
the kidney, brain, and testis as a selenium source for selenoprotein synthesis. We recently
demonstrated that apolipoprotein E receptor-2 (ApoER2) is required for Sepp1 uptake by the
testis and that deletion of ApoER2 reduces testis and brain, but not kidney, selenium levels.
This study examined the kidney Sepp1 uptake pathway. Immunolocalization experiments
demonstrated that Sepp1 passed into the glomerular filtrate and was specifically taken up by …