Endothelin Concentration in Plasma of Healthy Dogs and Dogs With Congestive Heart Failure, Renal Failure, Diabetes Mellitus, and Hyperadrenocorticism

Abstract

Plasma concentrations of endothelin (ET)‐1 and ‐3 were determined simultaneously in dogs with various pathophysiological conditions, because these peptides may display different pharmacological profiles. The study pays special attention to the characterization of plasma ET immunoreactivity (ET‐IR), using high‐pressure liquid chromatography (HPLC) analysis with off‐line detection by radioimmunoassay (RIA). In most sick dogs evaluated total plasma ET‐1‐IR concentration did not differ from that of healthy dogs. However, HPLC analysis of their total plasma ET‐1 ‐IR revealed distinct ET‐IR profiles. Big‐ET‐1, which is barely detectable in control dogs, does represent the predominant ET in sick dogs. Regardless of the pathophysiological conditions, considerable amounts of high‐molecular weight ET‐1‐IR, most likely aggregated ET‐material, was found consistently. With respect to ET‐3, we constantly observed moderately increased concentrations, though no major difference of molecular pattern was evident between healthy and sick dogs. The data show a distinct regulation of ET‐1 and ET‐3 in dogs. Furthermore, specific molecular forms of ET‐IR were found to occur in various diseases. The endothelins may therefore prove to be of diagnostic importance in the pathophysiology of vascular diseases. © 1995 American College of Veterinary Internal Medicine