Immunohistochemistry of renin in human diseased kidney.

The distribution of renin in human kidney was investigated by immunofluorescence and the peroxidase-antiperoxidase (PAP) procedure at the light and ultrastructural level. In three cases of juxtaglomerular renin-secreting tumors, renin was localized within the cytoplasm of tumor cells. In kidney biopsies, a semi-quantitative assessment was carried out, taking into account the size and the number of immunostained juxtaglomerular apparatuses. In 12 cases of ischemic kidneys and 8 cases of segmental renal hypoplasia, the increase in immunostaining for renin was striking in altered areas, while spared areas remained negative. In 2 cases of Bartter's syndrome, the pattern was similar to that found in ischemic kidneys. The study was extended to a series of 133 needle kidney biopsies from patients with various glomerular and vascular diseases; the immunomorphological parameters were correlated with serum creatinine levels but not with blood pressure values. Post-embedding immunoelectronmicroscopy using the PAP procedure performed on two of the cases of renin-secreting tumors, showed renin in all types of secretory granules.