Intrarenal adenosine prevents hyperfiltration induced by atrial natriuretic factor.

The hyperfiltration action of atrial natriuretic factor (ANF) and glucagon is accompanied by an elevation of adenosine in urine. We employed adenosine deaminase to evaluate the role of intrarenal adenosine in glomerular hyperfiltration induced by those hormones. Administration of ANF (2 micrograms/kg/min) resulted in an increase in the glomerular filtration rate (GFR): 1.99 vs. 3.01 ml/min (p less than 0.02) which was associated with a rise of adenosine excretion 87 vs. 151 pmol/min. Similarly, infusion of glucagon (2 micrograms/kg/min) raised the GFR from 1.86 to 2.67 ml/min (p less than 0.02) and adenosine excretion from 105 to 178 pmol/min (p less than 0.02). Adenosine deaminase treatment (2 U x kg/min) did not change the basal GFR and renal plasma flow but decreased plasma adenosine level 0.64 vs. 0.18 microM (p less than 0.001) and its excretion: 93 vs. 13 pmol/min (p less than 0.01). In adenosine deaminase treated rats ANF dramatically increased the GFR from 2.09 to 4.18 ml/min (p less than 0.001) and fractional filtration from 0.29 to 0.57, and the increase persisted throughout infusion of ANF. Similarly, adenosine deaminase treatment potentiated and prolonged the effect of glucagon on the GFR. These data indicate that depletion in renal adenosine does not decrease the GFR and that adenosine is present at inhibitory concentrations only during hormonal stimulation of glomerular filtration. It is concluded that renal endogenous adenosine functions do restrain hyperfiltration induced by ANF or glucagon.