Atrial natriuretic peptide ANP

ANP is a polypeptide hormone that is secreted in large quantities by the atrial portion of the heart and from a variety of other mammalian cell types. It exerts many of its actions via activation of particulate guanylate cyclase [16, 134]. ANP is present in human follicular fluids [163] and specific ANP receptors have been identified in human spermatozoa [144]. Sperm chemotaxis to ANP was demonstrated by sperm accumulation in capillaries with ascending [6] and descending [192] gradients and by choice assays [192] (Table 4). It is not yet known whether ANP is involved in sperm chemotaxis in vivo and whether the physiological chemoattractant for human spermatozoa is an ANP-like substance. Since chemotaxis to ANP at physiological concentrations can be observed only in the presence of a neutral endopeptidase inhibitor such 

The regulation of collagen synthesis in response to ascorbic acid has been the most extensively documented, as described above. Acetylcholine receptor, cytochrome P-450, atrial natriuretic peptide (ANP), and other proteins have also been demonstrated to respond to ascorbic acid with substantial changes in their transcripts. 

Numerous studies have shown that the level of surface AChR increases in muscle cells in response to neural tissue and brain extracts (Neugebauer et al., 1985 Buc-Caron et al., 1983 Jessel et al., 1979). One such factor, ascorbic acid, increases the surface AChR level in rat-derived cloned L5 muscle cells (Knaack et al., 1986 Knaack and Podleski, 1985). Other factors, acetylcholine receptor-inducing activity (ARIA) and calcitonin gene related peptide (CGRP) also increase the sur- 

Rat primary muscle cells respond to ascorbic acid with a threefold increase in the a-mRNA level as in the case of L5 cells. However, the increase in the a-mRNA is not further translated into a corresponding increase in the a-subunit protein. This suggests that the increased expression of surface AChR in response to ascorbic acid may be controlled by the availability of only the a-subunit protein (Horovitz et al., 1989b). At present, it remains unknown whether AChR synthesis is regulated at the level of transcription or translation. 

a 28-amino acid peptide, is produced in the heart as well as the central nervous system (Needleman et ai, 1989). Forskolin, an activator of the cAMP-dependent pathway, enhances ANP production in a time-dependent and dose-related manner at the low concentration of 10 jxM, forskolin doubles ANP production compared to that in control cultures. This change is reflected by a corresponding increase in the pro-ANP mRNA level (Huang et ai, 1991). 

Along with 10 xM forskolin, ascorbic acid markedly increases the pro-ANP mRNA level in a dose-related manner 4.2- and 11.5-fold in cultures cotreated with 1 and 10 jlM ascorbic acid, respectively. At the same time, ascorbic acid stimulates cAMP production induced by forskolin. The synergistic effect of ascorbic acid and forskolin on ANP production may be mediated, at least in part, through the protein kinase A-dependent pathway (Huang et al., 1993). 

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Natriuretic Peptide Diuretics. Atrial natriuretic peptide (ANP), an endogenous diuretic, natriuretic, and vasodilator, is a peptide hormone primarily synthesized and stored by atrial cardiocytes, and secreted by the atria in response to mechanical stretch of the atria. It was discovered in the cmde extracts of atria in 1981 (51). ANP is also known as anaritide [95896-08-5] atrial natriuretic factor [104595-79-1] (ANF) auriculin ... 

The atrial natriuretic peptide (ANP) belongs to a family of hormones that have structural similarity and some biological actions in common, such as natriuresis and haemoconcentration. It is synthesized and secreted by the cardiac atrium in response to increased atrial pressure. ANP is believed to act physiologically in an opposing manner to AVP... 

Substances released by the heart as atrial natriuretic peptide (ANP) have also offered a new dimension when looking at regulators of circulation (see Sect. 5.2.3) (Y2). 

Atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) are members of a family of so-called natriuretic peptides, synthesized predominantly in the cardiac atrium, ventricle, and vascular endothelial cells, respectively (G13, Y2). ANP is a 28-amino-acid polypeptide hormone released into the circulation in response to atrial stretch (L3). ANP acts (Fig. 8) on the kidney to increase sodium excretion and glomerular filtration rate (GFR), to antagonize renal vasoconstriction, and to inhibit renin secretion (Ml). In the cardiovascular system, ANP antagonizes vasoconstriction and shifts fluid from the intravascular to the interstitial compartment (G14). In the adrenal cortex, ANP is a powerful inhibitor of aldosterone synthesis (E6, N3). At the hypothalamic level, ANP inhibits vasopressin secretion (S3). It has been shown that some of the effects of ANP are mediated via a newly discovered hormone, called adreno-medullin, controlling fluid and electrolyte homeostasis (S8). The diuretic and blood pressure-lowering effect of ANP may be partially due to adrenomedullin (V5). 

Atrial natriuretic peptide (ANP) is produced by specialized myocytes in the atria of the heart. Secretion is stimulated by increased filling and stretch of the atria in response to plasma volume expansion. The effects of ANP include vasodilation, diuresis (increased urine production), and increased sodium excretion. Taken together, these effects decrease blood volume and blood pressure toward normal. 

Atrial natriuretic peptide (ANP) released from myocardial cells in the atria of the heart inhibits the reabsorption of sodium from the collecting duct. The mechanisms of action of ANP include ... 

There are seven membrane forms of GC, designated GC-A to GC-G [33], Two forms, GC-A and GC-B (Mr = 120kDa), serve as receptors for atrial natriuretic peptide (ANP) and related peptides. ANP is a 28-amino-acid peptide isolated originally from cardiac atria as an important factor in the regulation of sodium excretion and blood pressure. GC-A binds ANP, as well as brain natriuretic peptide (BNP), and is located in vascular tissue and kidney. 

Atrial natriuretic peptide (ANP), 5 186-187 Atrial tachycardia, 5 101, 104, 108 Atrioventricular node, 5 80 Atromid-S, 5 145-146... 

In addition to its pump function, the heart is also a secretory organ. Cardiac cells produce two small peptides, the natriuretic factors, which oppose the vasoconstrictive actions of noradrenaline (norepinephrine) from the sympathetic nervous system and of the peptide angiotensin II. By causing vasodilation and natriuresis (increased excretion of sodium in the urine), atrial natriuretic peptide (ANP) secreted from the atria and B-type natriuretic peptide (BNP) secreted by both atria and probably more significantly, from the ventricles, reduce blood pressure. The stimulus to secretion of natriuretic peptides is wall stretch of the chambers of the heart, indicating volume and pressure overload of the vascular system. A third member of the natriuretic peptide family, CNP, is secreted by endothelial cells. 

The steroid hormone aldosterone (see p. 55) increases Na reuptake, particularly in the distal tubule, while atrial natriuretic peptide (ANP) originating from the cardiac atrium reduces it. Among other effects, aldosterone induces Na /K" ATPase and various Na" transporters on the luminal side of the cells. 

Whereas several peptides besides AVP are known to act synergistically with CRH, the only peptide candidate in humans that inhibits the HPA system at all regulatory levels of the system seems to be atrial natriuretic peptide (ANP). ANP has been shown to inhibit the stimulated release of CRH and ACTH in vitro and in vivo. This could be observed in humans as well, where ANP inhibits the CRH-induced ACTH (Keller et al. 1992), prolactin (Wiedemann et al. 1995), and cortisol secretion (StrOhle et al. 1998). ANP is not only synthesized by atrial myocytes (deBold et al. 1985) and released into the circulation, but is also found in neurons of different brain regions (Tanala et al. 1984) where specific receptors have been found. ANP receptors and immunoreactivity have been found in periventricular and paraventricular hypothalamic nuclei, the LC, and the central nucleus of the amygdala. 

Natriuretic peptides are naturally occurring substances in the body that oppose the activity of the renin-angiotensin system. The natriuretic peptide family consists of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). All three natriuretic peptides are synthesized from cleavage of a larger precursor polypeptide. In the ventricles and brain, the synthesis of BNP predominates ANP is synthesized by cardiac myocytes predominately in the atria and CNP is synthesized in the brain, blood vessels, and kidney. 

The endogenous hormone atrial natriuretic peptide (ANP), which acts to increase blood pressure, is, like many other effector peptides, excised from a longer native chain by an endopeptidase enzyme, that is, an agent that cleaves bonds well along the chain of amino acids. A small-molecule endopeptidase inhibitor lowers blood pressure by inhibiting the release of ANP. The inhibitor candoxatril (6-8) is now... 

Verspohl, E. J., Kuhn, M., and Ammon, H. P. T. (1988). RlNm5F (Rat insulinoma) cells possess receptors for atrial natriuretic peptide (ANP) and a functioning cGMP system Harm. Metab. Res. 20, 770-771. 

Related peptides include atrial natriuretic peptide (ANP) and urodilatin, a similar peptide produced in the kidney. Carperitide and ularitide, respectively, are investigational synthetic analogs of these endogenous peptides and are in clinical trials. 

The atria and other tissues of mammals contain a family of peptides with natriuretic, diuretic, vasorelaxant, and other properties. The family includes atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP). The peptides share a common 17-amino-acid disulfide ring with variable C- and N-terminals (Figure 17-5). A fourth peptide, urodilatin, has the same structure as ANP with an extension of four amino acids at the N-terminal. 

Structures of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). Sequences common to the peptides are indicated in green. 

Atrial natriuretic peptide (ANP) Several active peptides cleaved from precursor polypeptide of 126 residues Smooth muscle relaxation diuretic activity... 

Antihuman atrial natriuretic peptide (ANP) in serum 1997 C Factor (time) 10 (IPCR 5 hours, IRMA 2-3 days) Numata et al. [99]... 

In the example of a-human atrial natriuretic peptide (ANP), found at increased plasma levels in patients with heart failure, Numata et al. [70] demonstrated how IPCR sensitivity accelerated conventional assay procedures. For individual treatment of the cardiac patients, a prompt detection of atrial distension by the presence of the ANP marker would be desirable. Common ANP tests, however, take 2-3 days for the quantification of plasma by radiometric or ELISA techniques. With sandwich IPCR, the assay time could be shortened to 5 hours. A good correlation between IPCR and radiometric detection was maintained, combined with an additional improvement of the detection limit to 2 ng/L ANP. The average level of ANP in plasma for 25 patients with heart failure was found to be 117 100 ng/L, significantly higher than the typical level of 20 14 ng/L for healthy subjects. 

Active tissue uptake and binding to intra- and extravascular proteins, however, can substantially increase the volume of distribution of peptide and protein drugs, as for example observed with atrial natriuretic peptide (ANP) [56]. 

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