Quantitative estimation of renin‐containing cells in the juxtaglomerular apparatus in Bartter’s and pseudo‐Bartter’s syndromes

Our colleagues have previously observed the number of renin-immunoreactive juxtaglomerular apparatus (JGA) in renal specimens from patients with Bartter's and pseudo-Bartter's syndromes and from the normal individual. The question we have is to what extent the renin-containing cells actually increased their cell number. It is easy to count the number of renin-positive JGA in the specimens. The data showed that the number of renin-positive glomeruli was 10-17 times more frequent in both syndromes than in the normal control. A geometrical calculation simply indicated that the probability of detection of a cell mass in a thin cross-section is proportional to the length of the target structure. The number of renin-containing cells per JGA is proportional to the increased rate of detection of renin-immunoreactive JGA per unit area, namely 10-17 times. This is true when we assume that renin-containing cells are solely located along the afferent arteriole, where differentiation toward renin-secreting cell occurs in a few layers just outside the arteriole in a longitudinal direction.