Distribution of atrial natriuretic factor receptors in dog kidney fractions

Specific receptors for atrial natriuretic factor were studied in purified glomeruli, proximal tubules, thick ascending limbs of Henle's loops and collecting ducts from dog kidney. Glomeruli contain the highest concentration of receptor sites (pK = 9.9, B _max = 200 protein), followed by collecting ducts (pK = 9.4, B _max = 150 ). Low levels of receptor sites were also detectable in thick ascending limbs of Henle's loops (pK = 9.4, B _max = 36 ) while proximal tubules were completely devoid of specific binding sites. These results indicate that the glomeruli appear to be the primary site of interaction of artrial natriuretic factor in kidney cortex but that it might also act in the medulla on lower nephron tubular function.