Direct renal effects of endothelin in chronic hypoxic spontaneously hypertensive rats

1. The direct renal effects of endothelin (ET) were studied in eight chronic hypoxic rats (HA) and eight sea level (SL) spontaneously hypertensive rats (SHR). 2. After 4 weeks of exposure to simulated 5486 m (18,000 ft) hypoxia, all HA rats were in apparently good health, and baseline renal function, except effective renal blood flow, was not significantly different from SL rats. 3. Intrarenal arterial administration of ET (600 ng/kg per h) reduced ipsilateral renal excretion of water, sodium and potassium, glomerular filtration rate and effective renal plasma flow in both SL and HA rats to almost the same extent. 4. Administration of ET antiserum, however, increased the renal excretion of water in HA rats. 5. It is concluded that ET may play a role in the renal regulation of chronic hypoxic SHR.