An Immunoelectron-Microscopical Observation of Mouse Juxtaglomerular Cells in the Case of Experimental Hydronrophrosis

Abstract

Changes in juxtaglomerular (JG; renin-containing) cells in experimental hydronephrosis 1 month after ureteral ligation were investigated with immunoelectron-microscopical techniques. Two types of granules, electron dense (D) and lucent (L), were observed. D type granules were labeled more intensely with gold particles than those of L type. Granules intermediate between D and L types and exocytosis of D types were observed. In the cells containing D types exclusively, gold particles were restricted to the granules, whereas in the cells containing both D and L type granules, the particles were scattered throughout the cytoplasmic cytosol. The authors discuss the mechanisms of renin release in JG cells.

Comparative Study of Renin-Containing Cells. Histological Approaches.

“…Because of activation of JG cells in experimental hydronephrosis at 1 month after ligation, this is a useful model for investigation of renin release. Here, two types of granules, electron dense and lucent, are observed, suggesting two hypothetical mechanisms for renin release [63]. The first type occurs with the formation of exocytotic channels somewhat different in morphology from those found in other endocrine cells.…”

“…In late gestational periods, RC cells distributed throughout the intrarenal arterial trees, tend to decrease or disappear gradually, while they are located predominantly in the afferent glomerular vessels, corresponding to the morphological and physiological maturation of the JGA in sheep in late fetal life [100]. The intrarenal smooth muscle cells constituting vessel walls potentially possess the ability to synthesize renin [17], as demonstrated by experimental hydronephrosis using the mouse kidney [63,64,66] and by restriction of renal blood flow [71] or inhibition of ACE [38]. Because of elevated angiotensin II levels in newborn lambs [7], the RAS in the perinatal period plays an important role in the maintenance of circulatory homeostasis and in adaption to the changes of environment [83].…”

“…Analysis of the endocrine kidney after unilateral obstruction of the ureter provides some interesting findings about the origin of RC cells and the processing of renin granules [63,64,66] (Fig. 5).…”

Secretion-related structures of hypothalamo-hypophysial terminals in the rat posterior pituitary

“…Such hormone-releasing mechanism might be involved in one of "diacrinelike secretion" according to textbook classification. Up to date, there are a lot of studies suggesting the mechanism of "diacrine-like secretion" in the brain (21)(22)(23)(24) and kidney (25)(26)(27). This mechanism of secretion has been indicted to be occurred by a process which is also quite different from vesicular exocytosis and to be difficult to visualize.…”

Wnt7b and Its Direct Target p57kip2 in Renal Medulla Development

“…66 Renin is expressed mainly by juxtaglomerular cells in response to a change in renal homeostasis such as dehydration or hypertension. 38,39 Renin is an enzyme that hydrolyzes angiotensinogen to angiotensin I, which regulates blood pressure and fluid homeostasis. 67 Renin cells can differentiate and contribute to smooth muscle, mesangial cells, Bowman's capsule, and proximal tubules; and when homeostasis is disturbed, the former renin cells can de-differentiate and express renin again.…”