Acute effects of endothelin on renal hemodynamics and blood pressure in anesthetized rats

A novel and potent vasoconstrictive peptide, endothelin, has recently been purified from the culture supernatant of porcine aortic endothelium. In this study we examined the acute effects of synthetic endothelin on renal hemodynamics and blood pressure in anesthetized rats. Blood pressure and renal blood flow were measured before and 1, 2, 5, and 10 minutes after endothelin administration (1.0, 0.5, or 0.1 nM/kg body weight). After a transient fall, the blood pressure gradually increased. At five and ten minutes after administration of each of the three doses, the blood pressure was significantly elevated compared with baseline values. Renal blood flow decreased immediately after infusion of 1 nM/kg endothelin, and this decrease lasted throughout the observation periods, while 0.1 nM/kg endothelin did not affect renal blood flow. At 2, 5, and 10 minutes after infusion of 1.0 or 0.5 nM/kg endothelin, renal vascular resistance was significantly elevated. These hemodynamic alterations were dose-dependent. The results show that endothelin has potent hypertensive and renal vasoconstrictive effects in rats.