DEVELOPMENT AND APPLICATION OF A URODILATIN (CDD ANP-95-126)-SPECIFICRADIOIMMUNOASSAY

Urodilatin, a renal natriuretic peptide that is an analogue to circula ting atrial natriuretic peptide [alpha-ANP(99-126)], is measurable wit h a highly specific and sensitive radioimmunoassay. While most ANP ant ibodies cannot distinguish between urodilatin and other ANP analogues, the polyclonal urodilatin antibody specifically measures human urodil atin without any cross-reactivity to other ANP analogues. Urodilatin i s not detected in blood from healthy volunteers nor from cardiac patie nts. Urinary urodilatin accounts for only a part of total urinary ANP immunoreactivity. Urodilatin excretion closely parallels sodium excret ion in response to an acute volume load while changes in urinary immun oreactive ANP excretion do not reflect this renal response. We conclud e that specific urodilatin assays are required to explore further the physiological role of the renal natriuretic peptide.