Functional interpretation of the kidney juxtaglomerular apparatus using renin immunohistochemistry in Bartter's, pseudo-Bartter's and Conn's syndromes.

A comparative study of renin immunoreactivity in the juxtaglomerular apparatus of the human kidney was performed using the indirect immunoperoxidase method on a random microscopic sections. In renal biopsies taken from a case of Bartter's syndrome and a case of pseudo-Bartter's syndrome, the number of renin-positive juxtaglomerular apparatus (JGA) and the number of renin-positive cells in each JGA were significantly greater than in five renal specimens from control autopsy cases. In Conn's syndrome, none of the glomeruli contained renin-immunoreactive JGA. The number of renin-positive cells/mm2 in the renal cortex in cases of Bartter's and pseudo-Bartter's syndromes were 17.5 and 20.3, respectively, while in the control group, the range was 0.78-1.77 (mean 1.08). Together with other histochemical findings routinely examined in renal specimens, renin immunohistochemistry on random sections may be helpful in diagnostic renal pathology.