Atrial natriuretic peptide, brain natriuretic peptide and c-type natriuretic peptide: effects on testicular microcirculation and immunohistochemical localization.

The effect of local injection of atrial (ANP), brain (BNP) and C-type (CNP) natriuretic peptides and an ANP antagonist (HS-142-1) on testicular microcirculation and vasomotion was studied using laser Doppler flowmetry. The natriuretic peptides were also localized immunohistochemically within the testis. ANP, BNP-32, CNP-22 and CNP-53 all caused a dose-related increase in testicular blood flow. The effect of ANP was blocked by concomitant injection of the ANP antagonist. Immunoreactive (ir) CNP and ir BNP were found in Leydig cells whereas in ANP was observed in the seminiferous tubules. It is suggested that the natriuretic peptides could play a role in local regulation of the testicular microcirculation.