A2 adenosine receptors were characterized in human glomerular mesangial cells using [3H]5'-N-ethylcarboxamidoadenosine (NECA) as a tracer. There was a single group of receptor sites with a KD of 184 nM, and a number of sites of 317 fmol/mg of cell protein. Adenosine agonists increased 5'-nucleotidase activity via A2 receptor stimulation. The specific A2 agonist-NECA, at 0.1 and 1 micron, was a potent inhibitor of DNA synthesis.
2-Chloroadenosine 5'-Nucleotidase