Immunocytochemical localization of renin in kidneys and submandibular glands of SWR/J and C57BL/6J mice.

By using antibodies against highly purified submandibular gland renin, renin was localized immunocytochemically at the light and electron microscopic level in the submandibular glands and kidneys of adult male SWR/J and C57BL/6J mice. In accord with the data of Wilson et al. (Proc Natl Acad Sci USA 75:1185, 1977), renin was demonstrable only in the submandibular glands of SWR/J mice (high strain), where it was confined to the secretory granules of the granular convoluted tubules. In the kidneys of both strains, renin was confined to epithelioid cells of the juxtaglomerular apparatus. Electron microscopically immunostaining was restricted to the granules of the juxtaglomerular epitheliod cells. Morphometric analyses suggested that the kidney of the C57BL/6J mice contained more immunoreactive complexes per unit volume of cortex than SWR/J mice kidney. The data indicate that submandibular gland renin cross-reacts with kidney renin, but that genetic controls of these polypeptides in the two organs are independent.