Renin-positive granulated Goormaghtigh cells. Immunohistochemical and electron-microscopic studies on biopsies from patients with pseudo-Bartter syndrome.

It is difficult to distinguish between Goormaghtigh cells (G-cells) and media cells of the glomerular arterioles at the border of the Goormaghtigh cell field. Consequently, it has been unclear whether renin-positive G-cells are normally present and also whether renin-producing cells are recruited from the pool of renin-negative G-cells upon stimulation of the renin-angiotensin system (RAS). In the present study, immunohistochemical and electron-microscopic experiments have been carried out on serially sectioned kidney biopsies from four patients with pseudo-Bartter syndrome. The results strongly suggest that with long-lasting stimulation of the RAS all renin-negative ("secretory resting") G-cells are ultimately converted into renin-producing granular cells.