INVITRO AUTORADIOGRAPHIC LOCALIZATION OF ANP RECEPTORS IN RAT-KIDNEY AND ADRENAL-GLAND

Abstract

The radioligand 125I-ANP-(99-126) was used to map receptors for atrial natriuretic peptide (ANP) in the rat kidney and adrenal gland using in vitro autoradiography and computerized densitometry. In the kidney a very high density of receptors was found overlying glomeruli; these sites had a binding affinity constant of 0.48 +/- 0.06 X 10(-9) M-1 and a site concentration 818 +/- 108 fmol X mg protein-1. A moderate density of receptors was seen in the inner renal medulla; these sites had a binding constant of 0.9 +/- 0.2 X 10(9) M-1 and a receptor concentration of 204 +/- 44 fmol X mg protein-1, and moderate receptor density was also seen in the inner stripe of the outer medulla overlying vasa ..