Juxtaglomerular Activity Research Articles

Relationship between juxtaglomerular apparatus and plasma renin activity in human reno-vascular hypertension.

Juxtaglomerular cell count (JGCC) and juxtaglomerular activity (JA) on the fragments of the ischemic kidney and plasma renin activity (PRA) in peripheral venous blood were studied in 26 renovascular patients. In 11 cases PRA was also measured in renal venous blood. JGCC and JA values were always above normal range and both were significantly related to the PRA values in peripheral venous blood, while only JA was related to the PRA values in renal venous blood. These data indicate that in human renovascular hypertension the juxtaglomerular apparatus is hyperplastic and hypergranulated: the correlation between its morphological appearance and PRA seems to indicate that the renin-angiotensin system may be in some way involved in the genesis of hypertension.

DUAL MECHANISM FOR EXPERIMENTAL HYPERTENSION

At least two separate processes give rise to renal hypertension—sodium retention and secretion of a renal pressor substance. Experimental evidence suggests that sodium retention plays no role in hypertension due to unilateral renal ischæmia with the opposite kidney in situ. Where the opposite kidney is removed, sodium retention generally assumes major importance and produces a form of hypertension which is qualitatively different. This explains discrepancies in observations upon renin levels and juxtaglomerular activity in experimental hypertension. There are important similarities between this dual mechanism in the rat and the human patient.

RENAL VEIN RENIN AND JUXTAGLOMERULAR ACTIVITY IN SODIUM-DEPLETED SUBJECTS.

Ten patients requiring surgery for renal cysts or calculi and having no evidence of secondary hyperaldosteronism were divided, as volunteers for special study, into experimental and control groups. After base line studies, the experimental group was given a diet containing 87 mEq of sodium and 1.0 g of chlorothiazide daily for ten days. Control subjects ate a normal diet. At operation, samples of peripheral and renal venous blood were obtained for measurement of renin activity and renal biopsy was taken for determination of the juxtaglomerular index. Increased renin in renal venous plasma and hypergranularity of the juxtaglomerular apparatus were found in sodium-depleted subjects but not in control subjects. These findings confirm results previously found in animals.