Equine cardiodilatin/ atrial natriuretic peptide. Primary structure and immunohistochemical localization in auricular cardiocytes.
Cardiodilatin (CDD)/atrial natriuretic peptide (ANP) is a 28-amino acid peptide hormone known to be synthesized in the heart of a large number of different vertebrates. It plays an important role in the regulation of blood pressure and natriuresis/diuresis. Since the cardiovascular system of the horse has to meet the highest requirements concerning its physiological performance, we intended to characterize the cardiodilatin/atrial natriuretic peptide system of this species. By means of immunohistochemistry and immunoelectron microscopy, we precisely identified auricular cardiocytes as the loci of CDD/ANP synthesis. Using aortic smooth muscle relaxation assay and CDD/ANP-ELISA, we succeeded in isolating the biologically active prohormone. We subsequently cloned the equine cDNA of the CDD/ANP precursor protein and deduced its primary sequence. The entire precursor protein is in good agreement with the CDD/ANP prohormones of other mammals. The deduced theoretical average Mr of equine CDD/ANP-1-126 is 13,764, corresponding to the molecular weight of purified peptide determined by ESI-MS. Our findings suggest that equine CDD/ANP is produced in auricular cardiocytes and the predominant storage form of CDD/ANP in the auricle is the prohormone CDD/ANP-1-126.
Richter
R
R
Lower Saxony Institute for Peptide Research, Hannover, Germany.
Mägert
H
H
Mifune
H
H
Schulz-Knappe
P
P
Forssmann
W
W
D000595:Amino Acid Sequence; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D008401:Gas Chromatography-Mass Spectrometry; D006325:Heart Atria / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D006736:Horses; D007124:Immunoenzyme Techniques; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D009318:Natriuresis / Q000502:physiology; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D011498:Protein Precursors; D009320:Atrial Natriuretic Factor; C040651:cardiodilatin