Effects of Endothelin on Systemic and Renal Haemodynamics and Neuroendocrine Hormones in Conscious Dogs

Abstract

1. The effects of endothelin on systemic and renal haemodynamics and plasma concentrations of neuroendocrine hormones including plasma renin activity, aldosterone, adrenocorticotropic hormone, cortisol, catecholamines and arginine vasopressin were investigated in 18 conscious dogs. 2. Bolus injection of 4 pmol of endothelin/kg did not cause any significant changes in haemodynamics. Mean arterial pressure was elevated by both doses of 40 pmol/kg [91 +/- 2 to 99 +/- 2 mmHg (12.1 +/- 0.3 to 13.2 +/- 0.3 kPa), P less than 0.05] or 200 pmol/kg [93 +/- 2 to 107 +/- 3 mmHg (12.4 +/- 0.3 to 14.3 +/- 0.4 kPa), P less than 0.01], the latter dose increasing cardiac output (14%, P less than 0.05) and heart rate (9%, P less than 0.05), and the former reducing these parameters (14% and 8%, P less than 0.05, respectively). 3. In contrast with the various changes in systemic haemodynamics, renal blood flow transiently increased immediately after bolus injection in a dose-dependent manner (28%, P less than 0.05, 50%, P less than 0.01 and 110%, P less than 0.01 with 4, 40 and 200 pmol of endothelin/kg, respectively). This transient elevation of renal blood flow was followed by a gradual decrease (16%, P less than 0.05; 31%, P less than 0.01 and 36%, P less than 0.01) at 10 min. 4. All neurohormones were elevated in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)