title: Regulation of steroidogenesis by atrial natriuretic peptide (ANP) in the rat testis: differential involvement of GC-A and C receptors.
abstract: Previous studies have established a stimulatory effect of natriuretic peptides (NP) on testosterone production in mouse Leydig cells as intense as that of LH. Chronic administration of ANP in mice, on the other side, reduced testosterone levels. So, the understanding of the role of ANP on testicular steroidogenesis has been impaired by discrepant findings. The aim of the present study was to clarify the physiological role of ANP in the rat testis steroidogenesis using a model that preserves the interactions between testis cells and a medium devoid of any circulating factors that could interfere with testosterone production. First, ANP was immunolocalized in the interstitial compartment of the rat testis, mainly in Leydig cells. We also determined the presence of ANP and both GC-A (guanylyl cyclase A) and C receptors by real-time PCR in testis. Perfusion in vitro of testis with ANP (1 and 3x10(-7)M) stimulated testosterone production in a time- and dose-dependent manner. On the other side, testosterone secretion induced by LH was blunted by ANP. Similar effect was obtained using the specific C receptor ligand, cANF, indicating the involvement of C receptor in such response. In conclusion, ANP stimulated testosterone production in the rat testis perfused in vitro but decreased testosterone production LH-induced, effect that seems to involve C receptor. To this extent, our results suggest the existence of a local and complex peptidergic system in the rat testis, involving ANP and its receptors that could importantly modulate the androgen biosynthesis.
authors.affiliation: Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Virgínia Mara
authors.initials: VM
authors.lastname: Pereira
authors.forename: Amilton P Raposo
authors.initials: AP
authors.lastname: Costa
authors.forename: Alzira Amelia Martins
authors.initials: AA
authors.lastname: Rosa-E-Silva
authors.forename: Maria Aparecida Ribeiro
authors.initials: MA
authors.lastname: Vieira
authors.forename: Adelina Martha Dos
authors.initials: AM
authors.lastname: Reis
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D006162:Guanylate Cyclase / Q000502:physiology*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000494:pharmacology; D008297:Male; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar; D017461:Receptors, Atrial Natriuretic Factor / Q000502:physiology*; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide / Q000502:physiology*; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis*
chemical_list: D018000:Receptors, Peptide; D013739:Testosterone; D009320:Atrial Natriuretic Factor; D007986:Luteinizing Hormone; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; C091715:atrial natriuretic factor receptor A