Angiotensin II immunoreactivity coexists with renin in the juxtaglomerular granular cells of the kidney.

Abstract

The multiple physiologic functions ofangiotensin H (All) are generally supposed to be mediated by the peptide generated in the blood circulation. In addition to this extracellular mechanism of AII formation, we have obtained immunohistochemical evidence for the intracellular synthesis ofAll in the kidney. Rats were perfused with fixative, and paraffin sections of the kidneys were processed with antisera against renin (EC 3.4.99.19), AII, and other components ofthe renin-angiotensin system. Renin immunoreactivity was regularly observed in the epithelioid granular cells in the media ofthe afferent vessel ofthe glomerulus. All immunoreactivity was found to coexist within the same cells. This observation points to an intracellular production of All in the juxtaglomerular epithelioid granular cells. AUl may then be released concomitantly with renin in the interstitial fluid and in the blood. The paracrine secretion of All could exert a local regulatory influence on the tonus of the glomerular vessels.

Expression of the mouse Na-K-2Cl cotransporter, mBSC2, in the terminal inner medullary collecting duct, the glomerular and extraglomerular mesangium, and the glomerular afferent arteriole.

“…Sections were incubated for 30 min in PBS containing 1% BSA, and then incubated with affinity-purified anti-mBSC2 antibody diluted in PBS plus 1% BSA overnight at 4 Њ C. After washes in PBS, sections were incubated for 1 h with Cy3 conjugated anti-rabbit IgG (Jackson ImmunoResearch, West Grove, PA) at room temperature. For double labeling experiments, sections were incubated with anti-mBSC2 antibody and anti-␣ smooth muscle actin (clone 1A4; Sigma Immunochemicals, St. Louis, MO), or antirenin antibody (kindly provided by T. Inagami [11]) and labeled with FITC-conjugated anti-mouse IgG (Jackson ImmunoResearch) or anti-rabbit IgG (Vector Labs, Burlingame, CA), respectively. For staining of macula densa, sections were incubated with anti-rBSC1 immune serum, an antibody specific for the apical Na-K-Cl cotransporter (6) and anti-Tamm-Horsfall an- Figure 3.…”

Angiotensinogen localization and secretion in the rat pancreas

“…In particular, local RAS components or tissue generation of Ang II have been detected in several organs such as brain (Phillips et al 1993, Sernia 1995, pituitary (Thomas & Sernia 1990a), adrenal glands (Vinson 1995, Mulrow & Franco-Saenz 1996, heart (Dostal 2000), kidneys (Celio 1981, Hunt et al 1992, Darby & Sernia 1995, gonads (Thomas & Sernia 1990b, Vinson et al 1997) and pancreas (Leung et al 1998, 1999, Tahmasebi et al 1999, Leung & Carlsson 2001). The role played by these tissue RAS is not well understood and they have been proposed to regulate local blood flow or to fulfil specific functions according to the tissue.…”

Review: Intrarenal angiotensin II levels in normal and hypertensive states

“…Studies utilising immunohistochemical techniques demonstrated that Ang I and Ang II are co-localised with renin in JGA cells and vascular smooth muscle cells of the afferent arteriole. [53][54][55][56] These studies suggested that Ang II could be formed or internalised into the smooth muscle cells. 32 Because there is no direct evidence for intracellular angiotensinogen in vascular smooth muscle cells, it is more likely that Ang I and/or Ang II are internalised via receptor-mediated endocytosis in smooth muscle cells.…”