Immunocytochemical localization of ProANF 1-30, ProANF 31-67, atrial natriuretic factor and urodilatin in the human kidney.

Abstract

Whether ProANF 1-30 [first 30 amino acids (a.a.) of the 126-a.a. atrial natriuretic factor (ANF) prohormone] and ProANF 31-67 (a.a. 31-67 of this prohormone) with their natriuretic and diuretic properties are present within the human kidney is unknown. In the present investigation, ProANFs 1-30 and 31-67 as well as ANF (a.a. 99-126) of the ANF prohormone localized to the subbrush border of the pars convoluta and pars recta of the proximal tubules of the human kidney with immunoperoxidase staining. Immunofluorescent studies revealed that each of these peptides had a strong inclination for the perinuclear region in the proximal and distal tubules. ProANFs 1-30, 31-67 and 99-126 (i.e. ANF) also localized with both immunoperoxidase and immunofluorescent staining to the coritcal collecting ducts, glomeruli, and peritubular and interstitial blood vessels. ANF immunoperoxidase staining was particularly striking in the endothelium of interstitial arteries and vasa recta. In the glomeruli, prominent staining was noted in the peripheral glomerular capillary wall and in some of the visceral epithelial cells. In contrast, urodilatin (i.e. a.a. 95-126 of the ANF prohormone) was not found in the proximal tubules, but weak staining was found in the distal tubules and interstitial vessels with some but not all glomeruli, peritubular vessels, cortical collecting tubules and outer medullary nephrons weakly staining by immunoperoxidase and immunofluorescent methods. The whole prohormone being present in the kidney was suggested by immunological recognition of both the N- and C-termini of the ANF prohormone by radioimmunoassays.(ABSTRACT TRUNCATED AT 250 WORDS)