Studies on renal juxtaglomerular cells. III. The effects of experimental renal disease and hypertension in the rat.

Hypertension in rats produced by constriction of one renal artery was associated with degranulation of juxtaglomerular cells in the contralateral, undamped, kidney. These findings are consistent with those of other investigators. Furthermore, the degree of granulation (JGI) in the unclamped kidney was inversely correlated with the level of blood pressure (r = -0.7). Degranulation of JG cells also occurred in rats made hypertensive by application of a "figure-of-eight" ligature to one kidney and removal of the other one, except when the interference in blood supply was so severe that scarring resulted. In these damaged areas, granules persisted or increased in number even though they were decreased in adjacent relatively normal areas. Occlusion of one ureter in rats produced severe hydronephrosis in the homolateral kidney and an elevation in blood pressure. Juxtaglomerular cell granules persisted in the hydronephrotic kidney but were decreased in the contralateral one. This finding confirmed the results of the above experiments. Unilateral nephrectomy in comparable rats had no effect on the degree of granulation of JG cells in the remaining kidney or on the level of blood pressure under the conditions of these experiments. The possibility that degranulation of JG cells in the contralateral kidney in the rats described above was due to compensatory hypertrophy was thereby excluded. An elevation in blood pressure was therefore implicated as an important factor in causing degranulation of juxtaglomerular cells.