Corin: an ANP protease that may regulate sodium reabsorption in nephrotic syndrome.

The serine/threonine protease corin, which proteolytically activates atrial natriuretic peptide (ANP), is reduced in the kidneys of animals with nephrotic syndrome and glomerular nephritis. Polzin et al. provide evidence for a linkage between the decreased corin and β-epithelial sodium channel, phosphodiesterase 5, and cGMP-dependent protein kinase II in the nephrotic kidney. They propose that decreases in cGMP resulting from the reduced corin may be responsible for the Na(+) retention and volume expansion that are hallmarks of these kidney diseases.