Metabolism of adenine nucleotides in human blood.

摘要: Biologically active concentrations of potently vasoactive and platelet-active adenine nucleotides are generated in plasma by a variety pathophysiological mechanisms. Although there is evidence that ATP ADP inactivated endothelial ectonucleotidases, has been little attempt to study the metabolic routes their catabolism blood or assess contribution this process clearance vivo. Therefore, we have studied rates patterns ATP, ADP, AMP whole blood, plasma, isolated cells. Rates degradation each nucleotide cell-free ranged from 0.07-0.32 nmol/min/ml with 1 microM substrates 1.1-3.6 100 substrates. The pattern indicated sequential dephosphorylation ATP----ADP----AMP----adenosine occurs. In was similar although (but not AMP) breakdown more rapid. This due leukocyte ectonucleotidase activity. use selective inhibitors demonstrated nonspecific phosphatase activity 59-nucleotidase distinct ATPase ADPase. leukocytes, ADPase activities were distinguishable, contributed substantially blood. Leukocyte did measurably contribute By comparison, ecto-ATPase ecto-ADPase on cultured human umbilical vein cells those leukocytes while per 10(6) equivalent soluble ml plasma.(ABSTRACT TRUNCATED AT 250 WORDS)