Cellular localisation of atrial natriuretic factor in the human kidney

We have localised atrial natriuretic factor (ANF) in the human kidney by immunocytochemistry and radioimmunoassay. ANF is specifically visualised in the distal convoluted tubule cells and the intercalated cells of the connecting tubules and collecting ducts of the human nephron. The number of immunoreactive cells and tissue values for the peptide were compared between samples from normal kidneys and biopsies obtained from hypertensive patients, in whom the tissue ANF immunoreactivity was found to be reduced. Specific experiments are necessary to establish whether renal ANF is synthesised de novo or captured through endocytosis by the renal tubular cells. The possible functional roles of renal ANF are discussed.