RENAL EFFECTS OF IV ADENOSINE INFUSION IN HUMANS

The effects of systemic intravenous (i.v.) infusion of adenosine on re nal blood flow and glomerular filtration in eight healthy, awake femal es have been examined. Renal blood flow and glomerular filtration rate were measured as the clearance of para-aminohippuric acid (PAH) and i nulin, respectively. Following basal sampling adenosine was infused i. v. at successive rates of 60 and 80 mug kg-1 min-1 for 30 min at each rate. Plasma clearance of PAH showed a minor, but non-significant, inc rease from 697 +/- 41 to 775 +/- 97 ml min-1. However, the arterial pl asma concentration of PAH decreased by 17 +/- 4% (P<0.001), indicating that there was a small increase in renal blood flow. Inulin clearance was reduced from 123 +/- 14 to 88 +/- ml min-1 1.73 m-2 (P<0.01). The resulting filtration fraction was reduced from 18 +/- 1 to 11 +/- 1 ( P<0.001). The K+/Na+ excretion ratio increased from a basal value of 1 0 +/- 1 to 42 +/- 11 (P<0.01) at the highest dose of adenosine, and re nal oxygen consumption decreased from 17 +/- 2 to 9 +/- 1 ml min-1 (P< 0.001). In conclusion, i.v. infusion of adenosine in healthy, awake su bjects causes a minor increase in total renal blood flow and a marked reduction in glomerular filtration. This shows that adenosine also exe rts a vasodilatory effect in the renal circulation, primarily on postg lomerular arterioles. In addition, adenosine may produce an aldosteron e-like effect on salt excretion, and a reduction in renal oxygen consu mption.