Effects of Adenosine Compounds on Renal Function and Renin Secretion in Dogs

In anesthetized salt-depleted dogs, infusion of adenosine (20 to 500 μg/min) directly into a renal artery induced an initial decrease of renal blood flow for 1 to 2 minutes but did not change or slightly increased this flow during the steady state. Statistically significant decreases occurred in glomerular filtration rate, filtration fraction, sodium excretion, and renal venous renin activity. Calculated afferent arteriolar resistance increased and efferent resistance decreased. 5′-AMP (50 to 200 μg/min) induced changes which were smaller but qualitatively similar to those of adenosine. ATP (50 to 500 μg/min) induced no initial reduction in blood flow, and, during the steady state, caused a significant increase in blood flow and decreases in glomerular filtration rate, filtration fraction, sodium excretion, and renal venous renin. Efferent resistance decreased but afferent resistance did not change. Cyclic AMP (1 to 5 mg/min) caused a very small initial transient reduction in blood flow but induced changes similar to those of ATP during the steady state. Inosine (200 μg/min) and inosine-5′-monophosphate (50 to 200 μg/min) produced no detectable effects. It is suggested that adenosine or 5′-AMP may be normal mediators of both autoregulation and renin secretion.