Synthesis and localization of C-type natriuretic peptide in mammalian kidney

Abstract

We have previously demonstrated the synthesis of atrial natriuretic factor (ANF) in the distal cortical nephron of the rat kidney. We now report the synthesis of C-type natriuretic peptide (CNP) in the rat, mouse, and human nephron. CNP mRNA was initially detected in the rat and mouse kidney, as well as in three transformed cell lines isolated from the proximal and distal nephron, using reverse transcription-polymerase chain reaction (RT-PCR). Confirmation of the kidney PCR product was performed by nucleotide sequence analysis and Southern hybridization. Northern hybridization of rat brain CNP cDNA to human kidney polyadenylated RNA detected a 1.4-kb gene transcript. Rat nephron segments were microdissected and subjected to RT-PCR to localize CNP mRNA. CNP mRNA was detected in the proximal convoluted tubule, cortical collecting duct, medullary thick limbs, and inner medullary collecting ducts. CNP, as detected by immunohistochemistry, was found to colocalize with CNP mRNA.

Increased C-type natriuretic peptide mRNA expression in the kidney of diabetic rats

“…Several investigations have also demonstrated CNP mRNA in the rat kidney (Suzuki et al 1993, Dean et al 1994, Terada et al 1994 and cultured mouse proximal cells (Suzuki et al 1993). CNP mRNA has even been found in microdissected nephron segments of the proximal convoluted tubule, the cortical collecting duct and the medullary thick limbs of rats (Dean et al 1994).…”

“…1991, Suzuki et al 1993, Dean et al 1994, Mattingly et al 1994. Several investigations have also demonstrated CNP mRNA in the rat kidney (Suzuki et al 1993, Dean et al 1994, Terada et al 1994 and cultured mouse proximal cells (Suzuki et al 1993).…”

“…Though initially identified in porcine brain (Sudoh et al 1990), CNP immunoreactivity and mRNA have recently been found outside the brain (Komatsu et al 1991, Stingo et al 1992, Suga et al 1992, Vollmar et al 1993. Several investigations have also demonstrated that CNP protein (Komatsu et al 1991, Ueda et al 1991, Suzuki et al 1993, Dean et al 1994, Mattingly et al 1994 and CNP mRNA (Suzuki et al 1993, Dean et al 1994, Terada et al 1994 are detectable in the kidney, suggesting that the kidney is a site for CNP production (Mattingly et al 1994). Although relatively little is known about the renal action of CNP, CNP may be involved in the regulation of water-electrolyte homeostasis as the ANP receptor-B (ANPR-B) is present in the kidney (Schultz et al 1989, Canaan-Kuhl et al 1992, Fraenkel et al 1994, Terada et al 1994 and CNP stimulates cGMP production by means of porcine kidney epithelial cells (Suga et al 1990, Shigematsu et al 1993, Terada et al 1994.…”

The atrial natriuretic peptide (ANP) system in the pronephros and mesonephros of Bufo bufo larvae

“…ANP may be produced in the mesonephros up to this stage, and then carry out an autocrine/paracrine action associated with the endocrine action of cardiac ANP. ANP production may continue in the adult mesonephros similar to what occurs in the mammalian kidney [40][41][42][43][44][45][46].…”

“…The vertebrate kidney is an important target organ for ANP; in fact this hormone helps regulate the volume of extracellular fluid and the electrolyte balance by increasing the secretion of water and salt by directly acting on the kidney [23]. Some authors [40][41][42][43][44][45][46] suggest that the mammalian kidney is also involved in the synthesis of the hormone.…”