Adenosine stimulates 5'-nucleotidase activity in rat mesangial cells via A2 receptors (original) (raw)
Because A, adenosine receptor activation stimulates adenylate cyclase and cyclic AMP induces 5'-nucleotidase expresslon m rat mesanglal cells. we examined the effect of adenosine and its analogs on 5'-nucleotidase activity m these cells. Az adenosine receptors were characterized usmg ['HIS'-N-ethylcarboxamidoadenosine (NECA) as a tracer. There was a single group of receptor sites with a k;, value of 0.53 PM and a number of sites of 1,317 fmol/mg. ['HINECA binding was inhlblted preferentially by A1 adenosme analogs and antagomsts Slmllarlq, the order of potency for CAMP stimulation was m favour of A2 adenosine analogs. Rat mesangial cells expressed surface 5'-nucleotidase actlvlty Exposure of cells for 48 h to adenosine analogs showed that at low concentrations A, analogs stimulated 5'-nucleotidase actlvlty These results mdlcate that adenosmr upregulates activity of 5'-nucleotidase, the enzyme responsible for Its local formatlon. via AZ receptor stlmulatlon and increase m CAMP productlon.
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