Effects of Atrial Natriuretic Peptide on Renal Function and Renin Release in the Isolated Perfused Rat Kidney

抄録

The effects of synthetic atrial natriuretic peptide (ANP) on the renal hemodynamics, glomerular filtration rate (GFR), fluid and electrolyte excretion and renin release were studied in the isolated perfused rat kidney (IPK). When 10^-9mol of ANP was administered in 75ml of perfusate, the renal vascular resistance (RVR) was transiently decreased for 3 to 5min, thereafter increased for 30min and then tended to return to the control level. ANP increased the GFR (0.55±0.08 to 0.71±0.07ml/min), urine flow (UV) (0.018±0.002 to 0.194±0.028ml/min), absolute Na excretion (UNaV) (1.83±0.03 to 17.93±2.71μEq/min) and absolute K excretion (UKV) (0.67±0.13 to 2.33±0.18μEq/min). The addition of indomethacin or mefenamic acid to the perfusate before the administration of ANP exerted no influence on any of the effects of ANP. Renin release was inhibited by approximately 50% compared to the ANP-free control group. With the administration of ANP, UV and UNaV reached a peak 15-20min after the GFR reached a peak and remained elevated after the GFR fell below the control level. These findings suggest that 10^-9mol of ANP causes natriuresis and renin suppression in the IPK, and that the natriuresis is prostaglandin-independent and cannot be explained only by an increase in GFR.