Alteration of atrial natriuretic peptide binding sites in spontaneously hypertensive rats

Atrial natriuretic peptide (ANP) binding sites were studied by quantitative autoradiography in young (4-week-old) and adult (14-week-old) spontaneously hypertensive rats (SHRs) and age-matched Wistar-Kyoto (WKY) control rats. Young SHRs had fewer ANP binding sites in the smooth muscle layer of thoracic aorta. Both young and adult SHR had undetectable ANP binding in superior cervical and stellate sympathetic ganglia, pituitary gland, thymus and spleen, and lower binding in subfornical organ and choroid plexus. Conversely, in young SHRs and WKY rats, ANP binding site density was similar in adrenal zona glomerulosa, kidney glomeruli, and papilla. The SHRs have notable tissue specific decrease in ANP binding site concentration. This alteration may relate to the pathophysiology of genetic hypertension.