Post-translational processing of atrial natriuretic factor by adult rat atrial cardiocytes in culture

1993 ◽  
Vol 71 (7) ◽  
pp. 497-505 ◽  
Author(s):  
Gilles R. Dubé ◽  
Mercedes L. Kuroski - de Bold ◽  
Adolfo J. de Bold
Keyword(s):  
Molecular Weight ◽  
Atrial Natriuretic Factor ◽  
Average Rate ◽  
Primary Cultures ◽  
Low Molecular Weight ◽  
Nuclear Staining ◽  
Adult Rat ◽  
Natriuretic Factor ◽  
Atrial Cardiocytes ◽  
Atrial Natriuretic

Post-translational processing of the cardiac polypeptide hormone atrial natriuretic factor (ANF) was studied using primary cultures of cardiocytes derived from adult rat atria. Atrial cardiocytes attached to microcarrier beads were maintained for up to 15 days under continuous superfusion in minichromatographic columns. The cultures were characterized for their ability to store, process, and release ANF and by immunofluorescence microscopy for ANF, desmin, and myosin. Nuclear staining using the fluorescent DNA stain Hoechst 33258 was carried out to determine the total number of cells in culture. Column eluates were assayed for ANF by radioimmunoassay and analyzed by reverse phase high-performance liquid chromatography. For comparison purposes, superfusion experiments using freshly isolated cardiocytes supported in Bio-Gel P2 were carried out. Freshly isolated atrial cardiocytes stored high molecular weight ANF (5.2 ± 1.9 pmol/μg DNA) and released mostly (83.3 ± 6.7%) low molecular weight ANF, at an average rate of 97 ± 18 fmol∙min−1∙μg−1 DNA. The cell content and the rate of release of ANF after 15 days in culture were 1.3 ± 0.4 pmoi/μg DNA and 1.7 ± 0.4 fmol∙min−1∙μg−1 DNA, respectively, and 62.7 ± 6.3% of the released peptide was of a low molecular weight. There was no correlation between changes in cell population and the extent of processing. Cultures of noncardiocytes, superfused with exogenous proANF, did not significantly process proANF to a lower molecular weight peptide. The present investigation shows that adult rat atrial cardiocytes, maintained superfused in microcarrier culture and in a serum-supplemented medium for up to 15 days, retain phenotypic and biochemical characteristics normally associated with the dual contractile–endocrine nature of mammalian atrial cardiocytes in vivo. The results obtained in the present work strongly support the view that ANF post-translational processing is an intrinsic property of the atrial cardiocytes and is independent of any other cell type.Key words: atrial natriuretic factor, post-translation processing, cardyocytes, adult rats, cell cultures.

Atrial Natriuretic Factor: Sodium Transport in Human Erythrocytes

1984 ◽  
Vol 67 (4) ◽  
pp. 403-405 ◽  
Author(s):  
Nick C. Trippodo ◽  
Francis E. Cole ◽  
Allan A. MacPhee
Keyword(s):  
Molecular Weight ◽  
Sodium Transport ◽  
Atrial Natriuretic Factor ◽  
Gel Filtration ◽  
Human Erythrocytes ◽  
Low Molecular Weight ◽  
Sodium Efflux ◽  
Natriuretic Factor ◽  
Cotransport System ◽  
Atrial Natriuretic

1. The effect of partially purified rat atrial natriuretic factor on sodium efflux from sodium-loaded human erythrocytes was studied. 2. High molecular weight (10000–30000) and low molecular weight (3000–10000) fractions of atrial extract were prepared by gel filtration; they had natriuretic activity in rats. 3. Neither fraction affected sodium efflux in erythrocytes. 4. The results suggest that atrial natriuretic factor acts in the kidney by mechanisms other than through inhibition of the Na+-K+ exchange pump or the Na+-K+ cotransport system.

scholarly journals Contribution of blood and systemic circulation to the processing of pro-(atrial natriuretic factor)

1988 ◽  
Vol 250 (3) ◽  
pp. 665-670 ◽  
Author(s):  
K K Murthy ◽  
G Thibault ◽  
M Cantin
Keyword(s):  
Atrial Natriuretic Factor ◽  
Secretory Granules ◽  
Systemic Circulation ◽  
Initial Distribution ◽  
Metabolic Clearance ◽  
Time Intervals ◽  
Natriuretic Factor ◽  
Atrial Cardiocytes ◽  
Hydrolysis Of ◽  
Atrial Natriuretic

Atrial natriuretic factor-(Asn1-Tyr126)-peptide, the 13.6 kDa propeptide of atrial natriuretic factor (ANF), is stored in the secretory granules of atrial cardiocytes. ANF-(Ser99-Tyr126)-peptide, the 28-amino-acid species, is the circulating form of this hormone in the rat. As the site of maturation of the prohormone is still unknown, the present study was undertaken to understand the contribution of the circulation to the maturation process of pro-ANF. 125I-ANF-(Asn1-Tyr126)-peptide was incubated with whole rat blood, plasma or serum for different time intervals, and the products were analysed. There was minimal activation of the propeptide in either whole blood or plasma. Incubation with serum, however, resulted in the formation of an 11 kDa and a 3 kDa peptide which corresponded respectively to the N-terminal and C-terminal parts of the propeptide. These results suggest that hydrolysis of the propeptide in serum is brought about by enzymes that may be stimulated during coagulation but which may not play a major role in the activation of pro-ANF in the circulation. Plasma analysis at different time intervals after prohormone injection indicated a non-specific hydrolysis of the pro-ANF molecule. The disappearance rate curves, obtained with radiolabelled pro-ANF, suggested the presence of two components with half-lives of 2.1 +/- 0.4 min and 52.5 +/- 8.4 min respectively. A metabolic clearance rate of 1.49 +/- 0.22 ml/min and an initial distribution volume of 47.4 +/- 8 ml were calculated. These results indicate that the maturation of pro-ANF to its active circulating form takes place before it is released into the circulation.

In vitro evidence for atrial natriuretic factor-(5-28) production by macrophages of adult rat thymi.

Endocrinology ◽  
1993 ◽  
Vol 132 (5) ◽  
pp. 2184-2190 ◽  
Author(s):  
M Throsby ◽  
Z Yang ◽  
D Lee ◽  
W Huang ◽  
D L Copolov ◽  
...  
Keyword(s):  
Atrial Natriuretic Factor ◽  
Adult Rat ◽  
Natriuretic Factor ◽  
Atrial Natriuretic
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