A novel cell type in the parathyroid glands of spontaneously hypertensive rats

Recently, we described a circulating hypertensive factor, present in the plasma of spontaneously hypertensive rats (SHR). This factor seems to be produced by the parathyroid gland but is not identical to parathyroid hormone (PTH). In view of these findings, we attempted to search for histological differences in parathyroid glands between SHR and normotensive Wistar-Kyoto (WKY) rats by light and electron microscopy. Novel cells, distinct from normal chief cells, were frequently found in parathyroid glands of SHR rats, whereas they were scarcely observed in WKY rats. Our findings suggest that the novel cells are involved in the development of hypertension in SHR rats.