Prolonged blood pressure elevation after endothelin administration in bilaterally nephrectomized rats.

The hemodynamic effect of a novel potent vasoconstrictive peptide (endothelin) on systemic blood pressure was studied in bilaterally nephrectomized and sham-operated rats under conscious and almost unrestrained condition. Following bolus IV administration of porcine endothelin, plasma endothelin concentration was measured by radioimmunoassay. After a transient decline, blood pressure was gradually elevated by endothelin administration. At 20, 30, and 40 minutes after injection, blood pressure was significantly elevated in bilaterally nephrectomized rats compared with sham-operated rats. Arterial plasma endothelin concentrations increased and rapidly decreased after injection in both rat groups. Bilateral nephrectomy significantly delayed the disappearance of endothelin from the plasma. These results suggest that the kidney plays a role in the plasma clearance of IV bolus endothelin administration and that the prolonged plasma half-life of endothelin is in part associated with the prolonged blood pressure elevation after endothelin administration in bilaterally nephrectomized rats.