Regulation of plasma adenosine levels in normal pregnancy.

The aim of this study was to investigate the possible mechanism of the regulation of plasma adenosine concentration [ADO] in normal pregnancy. We measured the activities of circulating enzymes that are involved in the production and metabolism of adenosine, and plasma [ADO] in nonpregnant (n = 14) and normal pregnant women (n = 14) in the third trimester. In pregnant women, the activity of plasma 5′-nucleotidase and plasma [ADO] were significantly elevated and plasma adenosine deaminase activity was significantly reduced. Enzymatic activities of both plasma enzymes appear to be changed in a way that would favor increased adenosine concentrations.