ENDOTHELIN CONCENTRATION IN PLASMA OF HEALTHY DOGS AND DOGS WITH CONGESTIVE-HEART-FAILURE, RENAL-FAILURE, DIABETES-MELLITUS, AND HYPERADRENOCORTICISM

Plasma concentrations of endothelin (ET)-1 and -3 were determined simu ltaneously in dogs with various pathophysiological conditions, because these peptides may dis play different pharmacological profiles. The s tudy pays special attention to the characterization of plasma ET immun oreactivity (ET-IR), using high-pressure liquid chromatography (HPLC) analysis with off-line detection by radioimmunoassay (RIA). In most si ck dogs evaluated total plasma ET-1-IR concentration did not differ fr om 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 de tectable in control dogs, does represent the predominant ET in sick do gs. Regardless of the pathophysio-logical conditions, considerable amo unts of high-molecular weight ET-1-IR, most likely aggregated ET-mater ial, was found consistently. With respect to ET-3, we constantly obser ved 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, spe cific molecular forms of ET-IR were found to occur in various diseases . The endothelins may therefore prove to be of diagnostic importance i n the pathophysiology of vascular diseases.