TISSUE DISTRIBUTION AND LOCALIZATION OF NATRIURETIC PEPTIDE RECEPTOR SUBTYPES IN STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

Objective To investigate tissue distribution and localization of the n atriuretic peptide receptor (NPR) subtypes' messenger RNA (mRNA) and t o compare their expression between stroke-prone spontaneously hyperten sive rats (SHR-SP) and Wistar-Kyoto (WKY) rats, Methods Total RNA was extracted from organs of SHR-SP and WKY rats aged 13 weeks, The mRNA l evel was examined by RNase protection assay, The localization of the t ranscripts was determined by in-situ hybridization, Results In SHR-SP aged 13 weeks, NPR-A was expressed most abundantly in the adrenal glan d, lung and aorta, in that order, NPR-B was expressed highly in the ut erus and ovary, and also in the lung, adrenal, and brain, NPR-C was ex pressed predominantly in the atrium and mesentery, less so in the lung , vein, and kidney, In the adrenal gland, NPR-A was expressed mainly i n zona glomerulosa cells. In the atrium, NPR-C was expressed throughou t the wall. In the mesentery, NPR-C mRNA was detected mainly in adipoc ytes, In the kidney, NPR-C was found predominantly in podocytes. Where as the levels of expression of NPR subtypes in most tissues examined d id not differ between SHR-SP and WKY rats, the NPR-C mRNA level was si gnificantly greater in the kidneys of SHR-SP than it was in those of W KY rats, Conclusions These results indicated that each NPR subtype had a distinct tissue distribution pattern and that the expression of NPR -C in the kidneys of SHR-SP was greater than that in the kidneys of WK Y rats.