UPTAKE AND DEAMINATION OF ADENOSINE BY BLOOD - SPECIES DIFFERENCES, EFFECT OF PH, IONS, TEMPERATURE AND METABOLIC INHIBITORS

1. 1. The uptake and/or deamination of adenosine has been measured in continuo in blood from 12 different species. 2. 2. In total blood, the highest uptake was found in chicken and rabbit, less in human and pig, much less in dog, rat, guinea pig, sheep, goat and cat and almost negligible in cow and horse. 3. 3. Adenosine is deaminated to a large extent by the plasma in sheep, goat, cow and cat. In the other species, the erythrocytes are mainly involved in uptake and deamination except in guinea pig and dog in which the platelets are largely responsible for the disappearance of adenosine. 4. 4. In human and canine blood, the inactivation of adenosine is highly dependent on temperature but rather insensitive to changes in pH between 6 and 8 or to ionic environment. 5. 5. In human blood, metabolic inhibitors such as KCN, NaF, malonate, 2,4-din itrophenol or ouabain do not affect adenosine uptake or adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) activity. p-Chloromercuribenzoate inhibits the deaminase activity without changing the uptake, whereas N-ethylmaleimide exhibits the opposite effects. © 1969.