natriuretic peptide was identified in 1983 and named atrial natriuretic peptide
(ANP). ANP is a 28-amino acid polypeptide resulting from the C-terminal end of
the prohormone proANP. It is largely produced in the cardiac atria, and ANP is
quickly secreted in response to atrial stretching. ANP has the following
- Increases glomerular
filtration rate by dilating afferent arterioles
- Inhibits the collecting ducts from reabsorbing sodium,
both directly and indirectly (by inhibiting aldosterone secretion)
- Inhibits release of renin
The renin-angiotensin system and ANP
function antagonistically in the maintenance of fluid/electrolyte balance and
secrete extremely small amounts of ANP, but elevated levels are found in
patients with left ventricular (LV) hypertrophy and mitral valve disease.
Biochemical structure of ANP:
ANP is synthesized as a 126 amino acidprecursor protein which is cleaved to produce a
96 aminoacid amino-terminal fragment and a 28 amino acid
carboxyl-terminal fragment. The carboxyl-terminal 28 amino acid fragment is the biologically active peptide and
has shorter half-life than the amino-terminal fragment.
Conserved residues are shaded and the line
within the ring represents the disulfide bond.
ProANP is the prohormone of ANP (ANP is stored as a
126–amino acid prohormone (proANP1–126)). After this prohormone is released it is then cleaved into equimolar amounts of the biologically active C-terminal peptide (ANP (99–126)) and the residual N-terminal peptide (NT-proANP (1–98)) in response to atrial wall stretch.
α-ANP has a half-life of 3-4 minutes thus is quickly cleared from circulation. ProANP (1-98) on the other hand, has a significantly longer half-life of 60-120 minutes leading to much higher concentrations in blood as compared to α-ANP.
Why Measure proANP (1-98)?
Atrial natriuretic peptide (ANP) has an important physiological roles in fluid homeostasis and cardiac pathology. The longer half life of proANP (1-98) offers advantages for measuring the ANP in the blood over α-ANP due to its lack of sensitivity to the pulsatile secretion of ANP. In fact,proANP (1-98) may provide better insight to the ANP status and its chronic secretion in the blood. Studies have shown that proANP serves as a
valuable and stable marker for several areas of research ranging from sepsis to
predicting and aiding in risk stratification for heart failure.
Diseases/conditions associated with increased ANP levels:
- Diabetes and Obesity
- Renal Disease/Renal dysfunction
- Asthma attacks
- Recent heart attack
- Heart failure/Cardiac impairment
- Sleep apnea
- Haviv, M. et al. “Atrial Natriuretic Peptidein Children with Pneumonia.” Pediatric Pulmonology 40:306–309(2005).
- Hoffman et al. “Prognostic Value of Plasma N-Terminal Pro-Brain Natriuretic Peptide in Patients With Severe Sepsis.” Circulation; 2005:112:527-534.
- Lauridsen, Bo K et al. “ProANP Plasma Measurement Predicts All-Cause Mortality in Acutely Hospitalized Patients: A Cohort Study.” BMJ Open 2013;3:e003288 doi:10.1136/bmjopen-2013-003288.
- Moro, Cedric et al. “Natriuretic Peptides: New Players in Energy Homeostasis.” Diabetes 2009; 12: 2726-2728.
- Robichaud, A. et al. “Plasma Atrial Natriuretic Peptide During Spontaneous Bronchoconstriction in Asthmatics. Peptides 1995;16(4):653-6.
- Suzuki, T et al. “The Role of the Natriuretic Peptides in the Cardiovascular System.” Cardiovascular Research 2001; 51: 489–494.
Related Resources Citing EagleBio Kits:
- Stanek, B. et al. “Prognostic evaluation of neurohumoral plasma levels before and during beta-blocker therapy in advanced left ventricular dysfunction” Journal of American Cardiology 2001; 38: 436-442.