Catabolism of adenine nucleotides favors adenosine production following exercise in patients with chronic heart failure.
BACKGROUND
Adenosine 5'-triphosphate is catabolized to adenosine 5'-monophosphate (AMP), which is further degraded by 2 pathways: deamination to inosine 5'-monophosphate and ammonia by AMP deaminase, or dephosphorylation to adenosine and inorganic phosphate by 5'-nucleotidase. Because adenosine is believed to be cardioprotective and we have reported that ammonia production decreased after exercise in patients with chronic heart failure (CHF), we determined if plasma adenosine levels after exercise increases in patients with CHF.


RESULTS
Maximal ergometer exercise tests with expired gas analysis were performed in 51 patients with CHF (age = 61 +/- 2 years, New York Heart Association [NYHA] class I/II/III = 19/18/14) and 20 age-matched normal controls. Serial changes in both plasma ammonia and adenosine levels were determined. The ratio for delta ammonia to peak work rate became smaller (control, NYHA I/II/III: 0.59 +/- 0.13/0.41 +/- 0.06/0.37 +/- 0.10/0.22 +/- 0.11 microg/dL x watts, respectively) and the ratio for delta adenosine to peak work rate was significantly higher in class III CHF (control, NYHA I/II/III: 0.93 +/- 0.21/0.86 +/- 0.14/1.11 +/- 0.27/2.92 +/- 0.67 nmol/L x watts, respectively).


CONCLUSIONS
In patients with CHF after exercise, the plasma levels of adenosine increased along with the decrease in the plasma levels of ammonia. Considering the physiologic cardioprotective actions of adenosine, the enhanced adenosine production after exercise may be an important adaptive response in patients with CHF.
Kinugawa
Toru
T
Department of Cardiovascular Medicine, Faculty of Medicine, Graduate School of Medicine, Tottori University, Yonago, Japan.
Fujita
Masashi
M
Ogino
Kazuhide
K
Kato
Masahiko
M
Osaki
Shuichi
S
Igawa
Osamu
O
Shigemasa
Chiaki
C
Hisatome
Ichiro
I
Kitakaze
Masafumi
M
D000227:Adenine Nucleotides / Q000378:metabolism*; D000241:Adenosine / Q000096:biosynthesis* / Q000097:blood; D000368:Aged; D000641:Ammonia / Q000097:blood; D001794:Blood Pressure; D002303:Cardiac Output, Low / Q000097:blood / Q000378:metabolism / Q000503:physiopathology*; D002316:Cardiotonic Agents / Q000097:blood / Q000378:metabolism*; D002908:Chronic Disease; D015444:Exercise; D005260:Female; D006321:Heart / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D019271:Hypoxanthine / Q000097:blood; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption
D000227:Adenine Nucleotides; D002316:Cardiotonic Agents; D019271:Hypoxanthine; D000641:Ammonia; D000241:Adenosine