scholarly journals Respective roles of kallikrein and endopeptidase 24.11 in the metabolic pathway of atrial natriuretic peptide in the rat

1990 ◽  
Vol 269 (3) ◽  
pp. 801-806 ◽  
Author(s):  
Y Vanneste ◽  
S Pauwels ◽  
L Lambotte ◽  
A Michel ◽  
R Dimaline ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Cleavage Product ◽  
Constant Infusion ◽  
Maximal Inhibition ◽  
Blood Samples ◽  
Endopeptidase 24.11 ◽  
Rapid Clearance ◽  
Atrial Natriuretic

The metabolism of atrial natriuretic peptide (ANP) and Cys-105-Phe-106-cleaved ANP (ANP) was studied during constant infusion of 125I-labelled peptides in rats. Analysis of circulating radioactivity indicated rapid clearance of ANP and ANP′, with mean half-lives of 0.42 and 1.04 min respectively. H.p.l.c. fractionation of plasma taken during the infusion of labelled ANP revealed the presence of three radioactive fragments, the major one co-eluting with 125I-ANP′. These fragments correspond to cleavage products previously found to be generated in vitro by the action of endopeptidase 24.11 (E-24.11). On evaluating the effects of peptidase inhibitors, a significant increase in the half-life of ANP was observed with phosphoramidon (t1/2 7.8 min) and aprotinin (t1/2 5.4 min). A maximal inhibition of ANP degradation was obtained when both inhibitors were given simultaneously (t1/2 15 min). In blood samples taken during infusion of 125I-ANP and phosphoramidon, the intact peptide accounted for more than 90% of total circulating radioactivity, and no cleavage product was present in detectable amounts. Phosphoramidon had no effect on the metabolism of infused ANP′. In contrast, when 125I-ANP′ was infused together with aprotinin, the rate of degradation of the infused peptide was reduced by more than 80%. It is proposed that two different peptidase activities, E-24.11 and a kallikrein-like proteinase, are responsible for the cleavage of ANP in the circulation. The Cys-Phe-cleaved ANP would in turn be degraded by kallikrein and not by E-24.11.

scholarly journals The hydrolysis of α-human atrial natriuretic peptide by pig kidney microvillar membranes is initiated by endopeptidase-24.11

1987 ◽  
Vol 243 (1) ◽  
pp. 183-187 ◽  
Author(s):  
S L Stephenson ◽  
A J Kenny
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Angiotensin I ◽  
Human Atrial Natriuretic Peptide ◽  
Pig Kidney ◽  
Angiotensin I Converting Enzyme ◽  
Endopeptidase 24.11 ◽  
Hydrolysis Of ◽  
Atrial Natriuretic

alpha-Human atrial natriuretic peptide, a 28-amino-acid-residue peptide, was rapidly hydrolysed by pig kidney microvillar membranes in vitro, with a t1/2 of 8 min, comparable with the rate observed with angiotensins II and III. The products of hydrolysis were analysed by h.p.l.c., the pattern obtained with membranes being similar to that with purified endopeptidase-24.11 (EC 3.4.24.11). No hydrolysis by peptidyl dipeptidase A (angiotensin I converting enzyme, EC 3.4.15.1) was observed. The contribution of the various microvillar membrane peptidases was assessed by including specific inhibitors. Phosphoramidon, an inhibitor of endopeptidase-24.11, caused 80-100% suppression of the products. Captopril and amastatin (inhibitors of peptidyl dipeptidase A and aminopeptidases respectively) had no significant effect. Hydrolysis at an undefined site within the disulphide-linked ring occurred rapidly, followed by hydrolysis at other sites, including the Ser25--Phe26 bond.

scholarly journals Hydrolysis of α-human atrial natriuretic peptide in vitro by human kidney membranes and purified endopeptidase-24.11. Evidence for a novel cleavage site

1988 ◽  
Vol 254 (2) ◽  
pp. 531-537 ◽  
Author(s):  
Y Vanneste ◽  
A Michel ◽  
R Dimaline ◽  
T Najdovski ◽  
M Deschodt-Lanckman
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Bond Cleavage ◽  
Human Kidney ◽  
Human Atrial Natriuretic Peptide ◽  
Endopeptidase 24.11 ◽  
Therapeutic Uses ◽  
Atrial Natriuretic

alpha-Human atrial natriuretic peptide (hANP) is secreted by the heart and acts on the kidney to promote a strong diuresis and natriuresis. In vivo it has been shown to be catabolized partly by the kidney. Crude microvillar membranes of human kidney degrade 125I-ANP at several internal bonds generating metabolites among which the C-terminal fragments were identified. Formation of the C-terminal tripeptide was blocked by phosphoramidon, indicating the involvement of endopeptidase-24.11 in this cleavage. Subsequent cleavages by aminopeptidase(s) yielded the C-terminal dipeptide and free tyrosine. Using purified endopeptidase 24.11, we identified seven sites of hydrolysis in unlabelled alpha-hANP: the bonds Arg-4-Ser-5, Cys-7-Phe-8, Arg-11-Met-12, Arg-14-Ile-15, Gly-16-Ala-17, Gly-20-Leu-21 and Ser-25-Phe-26. However, the bonds Gly-16-Ala-17 and Arg-4-Ser-5 did not fulfil the known specificity requirements of the enzyme. Cleavage at the Gly-16-Ala-17 bond was previously observed by Stephenson & Kenny [(1987) Biochem. J. 243, 183-187], but this is the first report of an Arg-Ser bond cleavage by this enzyme. Initial attack of alpha-hANP by endopeptidase-24.11 took place at a bond within the disulphide-linked loop and produced a peptide having the same amino acid composition as intact ANP. The bond cleaved in this metabolite was determined as the Cys-7-Phe-8 bond. Determination of all the bonds cleaved in alpha-hANP by endopeptidase-24.11 should prove useful for the design of more stable analogues, which could have therapeutic uses in hypertension.

scholarly journals Differential effects of doxorubicin on atrial natriuretic peptide expression in vivo and in vitro

2001 ◽  
Vol 34 (3-4) ◽  
Author(s):  
ASIM RAHMAN ◽  
MAHMOOD ALAM ◽  
SUDHA RAO ◽  
LIN CAI ◽  
CLARK LUTHER T. ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Differential Effects ◽  
Peptide Expression ◽  
Atrial Natriuretic

Isoproterenol induces release of atrial natriuretic peptide from rat atrium in vitro

1992 ◽  
Vol 262 (1) ◽  
pp. H285-H292 ◽  
Author(s):  
G. Agnoletti ◽  
A. Rodella ◽  
A. Cornacchiari ◽  
A. F. Panzali ◽  
P. Harris ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Mechanical Stimulation ◽  
The Other ◽  
Mechanical Activity ◽  
Mechanical Function ◽  
Rat Atria ◽  
Rat Atrium ◽  
Atrial Natriuretic

To investigate the mechanism underlying the release of atrial natriuretic peptide (ANP) in in vitro condition, isolated, superfused rat atria were subjected to adrenergic, chronotropic, and mechanical stimulation. First administration of isoproterenol (Iso; either 10(-9) or 10(-6) M) caused a release of ANP, which was transient. Subsequent increments in concentration of Iso always resulted in a much lower release of ANP, despite the increased effects on the mechanical function of the atria. Stretching of the atria resulted in a transient release of ANP. Subsequent increments in stretching were followed by decreasing release of ANP. The total score of ANP in atrial tissue after Iso and stretching was not measurably depleted. Pacing the atria with increasing frequency did not induce release of ANP. Depolarization with 40 mM KCl abolished the release of ANP in response to Iso but not the release induced by stretch. In the presence of low external Ca2+, which abolished mechanical activity, both Iso and stretch could still induce release of ANP. Propranolol abolished the release of ANP by Iso but not that induced by stretching. Prazosin did not affect the release by either stretch or Iso. Stretching the atria 20 min after administration of Iso did not cause any further release of ANP. On the other hand, adding Iso 20 min after stretching induced a release of ANP. It is concluded that Iso and stretch cause a transient release from isolated strips of atria. The amount of ANP released is not related to the dose of Iso or to the load applied. Mechanisms involved in the release mediated by the two stimuli are different.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct effect of α-human atrial natriuretic peptide on human vasculature in vivo and in vitro

1988 ◽  
Vol 74 (2) ◽  
pp. 207-211 ◽  
Author(s):  
A. Hughes ◽  
S. Thom ◽  
P. Goldberg ◽  
G. Martin ◽  
P. Sever
Keyword(s):  
Blood Flow ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Forearm Blood Flow ◽  
Renin Angiotensin System ◽  
Organ Bath ◽  
Human Atrial Natriuretic Peptide ◽  
Atrial Natriuretic

1. The effect of a α-human atrial natriuretic peptide (1–28) (ANP) on human vasculature was investigated in vivo and in vitro. Possible involvement of vascular dopamine receptors and the renin-angiotensin system in the response to ANP was also studied in vivo. 2. Forearm blood blow was measured by venous occlusion plethysmography. Isolated human blood vessels were studied using conventional organ bath techniques. 3. ANP (0.1–1 μg/min, intra-arterially) produced a dose-dependent increase in forearm blood flow, corresponding to a 163% increase in net forearm blood flow in the study arm. This action of ANP was not antagonized by (R)-sulpiride (100 μg/min, intra-arterially), a selective vascular dopamine receptor antagonist, or 50 mg of oral captopril, an inhibitor of angiotensin-converting enzyme. 4. ANP (1 nmol/l–1 μmol/l) produced concentration-dependent relaxation of isolated human arteries, including brachial artery, but was without effect on isolated human saphenous vein. 5. ANP produces vasodilatation in vivo and relaxes isolated human arterial smooth muscle. This action of ANP may contribute to its reported hypotensive effects in vivo.

Renal hemodynamic and natriuretic effects of manganese and interactions with atrial natriuretic peptide

1990 ◽  
Vol 258 (4) ◽  
pp. F998-F1004 ◽  
Author(s):  
H. M. Lafferty ◽  
M. Gunning ◽  
H. R. Brady ◽  
B. M. Brenner ◽  
S. Anderson
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Flow Rate ◽  
Plasma Flow ◽  
Collecting Duct ◽  
Hydraulic Pressure ◽  
Cgmp Production ◽  
Atrial Natriuretic

Manganese (Mn2+) is a cofactor for guanylate cyclase (GC), which is involved in the generation of guanosine 3',5'-cyclic monophosphate (cGMP), a second messenger for atrial natriuretic peptide (ANP) action. Mn2+ is also, however, a nonselective calcium-channel blocker. We examined the effects of infusion of MnCl2 into normal rats and its interaction in vivo and in vitro with GC and ANP. MnCl2 significantly increased glomerular filtration rate (GFR) and effective renal plasma flow rate (RPF). These effects were caused by selective afferent arteriolar vasodilatation, which allowed the glomerular capillary plasma flow rate and hydraulic pressure to rise, thus elevating single-nephron GFR. Urinary Na+ excretion (UNaV) also increased with MnCl2. The natriuresis was, unlike ANP, not mediated by GC activation and cGMP production, as MnCl2 had no effect on either urinary cGMP excretion or cGMP accumulation in intact inner medullary collecting duct cell (IMCD) suspensions, nor did it affect Na(+)-dependent oxygen consumption in these cells. When superimposed on an infusion of ANP, MnCl2 resulted in significant increases in UNaV, GFR, and RPF. These effects were associated with small but significant increments in urinary cGMP excretion. However, MnCl2 did not affect in vitro cGMP production in intact IMCDs or glomeruli in response to ANP stimulation. It is uncertain therefore whether the in vivo augmentation of the natriuretic effect of ANP by MnCl2 is related to GC activation and cGMP production.

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