Turnover of adenosine in plasma of human and dog blood

Am J Physiol. 1989 Apr;256(4 Pt 1):C799-806. doi: 10.1152/ajpcell.1989.256.4.C799.


To determine half-life and turnover of plasma adenosine, heparinized blood from healthy volunteers was incubated with radiolabeled adenosine in the physiological concentration range of 0.1-1 microM. Plasma levels of adenosine in vitro were 82 +/- 14 nM and were similar to those determined immediately after blood collection with a "stopping solution." Dipyridamole (83 microM) and erythro-9(2-hydroxynon-3yl)-adenine (EHNA) (8 microM) did not measurably alter basal adenosine levels but completely blocked the uptake of added adenosine. Inhibition of ecto-5'-nucleotidase with 100 microM alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP) reduced plasma adenosine to 22 +/- 6 nM. For the determination of adenosine turnover, the decrease in specific radioactivity of added [3H]adenosine was measured using a dipyridamole-containing stopping solution. Without altering basal adenosine levels, the half-life was estimated to be 0.6 s. Similar experiments were carried out with washed erythrocytes or in the presence of AOPCP, yielding half-lives of 0.7 and 0.9 s, respectively. When the initial adenosine concentration was 1 microM, its specific activity decreased by only 11% within 5 s, whereas total plasma adenosine exponentially decreased with a half-life of 1.5 s. Venous plasma concentrations were measured after relief of a 3-min forearm ischemia. Changes in plasma adenosine did not correlate well with changes in blood flow but were augmented in the presence of dipyridamole.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5'-Nucleotidase
  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Adenosine / blood*
  • Adenosine Diphosphate / analogs & derivatives
  • Adenosine Diphosphate / pharmacology
  • Adenosine Monophosphate / blood
  • Adenosylhomocysteinase
  • Animals
  • Blood Flow Velocity
  • Dipyridamole / pharmacology
  • Dogs
  • Forearm / blood supply
  • Half-Life
  • Humans
  • Hydrolases / blood
  • Nucleotidases / antagonists & inhibitors
  • Tritium


  • alpha,beta-methyleneadenosine 5'-diphosphate
  • Tritium
  • Adenosine Monophosphate
  • 9-(2-hydroxy-3-nonyl)adenine
  • Adenosine Diphosphate
  • Dipyridamole
  • Hydrolases
  • Nucleotidases
  • 5'-Nucleotidase
  • Adenosylhomocysteinase
  • Adenine
  • Adenosine