To investigate tissue distribution and localization of the natriuretic peptide receptor (NPR) subtypes' messenger RNA (mRNA) and to compare their expression between stroke-prone spontaneously hypertensive rats (SHR-SP) and Wistar–Kyoto (WKY) rats.
Total RNA was extracted from organs of SHRSP and WKY rats aged 13 weeks. The mRNA level was examined by RNase protection assay. The localization of the transcripts was determined by in-situ hybridization.
In SHR-SP aged 13 weeks, NPR-A was expressed most abundantly in the adrenal gland, lung and aorta, in that order. NPR-B was expressed highly in the uterus and ovary, and also in the lung, adrenal, and brain. NPR-C was expressed predominantly in the atrium and mesentery, less so in the lung, vein, and kidney. In the adrenal gland, NPR-A was expressed mainly in zona glomerulosa cells. In the atrium, NPR-C was expressed throughout the wall. In the mesentery, NPR-C mRNA was detected mainly in adipocytes. In the kidney, NPR-C was found predominantly in podocytes. Whereas the levels of expression of NPR subtypes in most tissues examined did not differ between SHR-SP and WKY rats, the NPR-C mRNA level was significantly greater in the kidneys of SHR-SP than it was in those of WKY rats.
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 WKY rats.
1From the Fourth Department of Internal Medicine, University of Tokyo School of Medicine, Bunkyo-ku, Tokyo
2Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan.
3Requests for reprints to Toshiro Fujita, Fourth Department of Internal Medicine, University of Tokyo School of Medicine, 3-28-6 Mejirodai, Bunkyo-ku, Tokyo 112, Japan.
Received 6 March 1997 Revised 16 June 1997 Accepted 15 July 1997