Immunoreactive renin in mouse adrenal gland. Localization in the inner cortical region

The existence of renin in the adrenal gland of the mouse was determined by its enzymatic activity and by immunohistochemical techniques using monospecific antibodies to mouse submandibular gland renin. The adrenal gland of mouse was found to contain a very high level of renin significantly greater than other mouse tissues except for the kidney and submandibular gland. Also, the renin level in mouse adrenal was significantly higher than that in adrenals of other species. This renin activity was distinct from the nonspecific renin-like activity of acid proteases in that its activity was optimal at neutral pH and specifically inhibited by antirenin antibody. Adrenal renin increased upon nephrectomy indicating that it is not derived from the kidney. Immunohistochemical studies localized the renin-immunoreactive substance to cells in the inner region of the cortex. The intensity of staining was highest in the innermost region and decreased in cells in outer layers.