Active and Inactive Renin in Individual Juxtaglomerular Apparatuses

1980 ◽  
Vol 59 (s6) ◽  
pp. 35s-36s
Author(s):  
A. Gillies ◽  
T. Morgan ◽  
W. Fitzgibbon
Keyword(s):  
Salt Intake ◽  
Active Form ◽  
Juxtaglomerular Apparatus ◽  
Macula Densa ◽  
Active Renin ◽  
High Salt Intake ◽  
Before And After ◽  
Inactive Renin ◽  
Inhibitor Of Protein Synthesis

1. Renin was measured in individual juxtaglomerular apparatuses before and after acidification in vitro.. 2. Active renin increased with delivery of extra sodium by microperfusion to the macula densa and this increase was similar to that achieved with acidification. 3. In rats pretreated with an inhibitor of protein synthesis active renin increased when extra sodium was delivered to the macula densa. 4. Salt intake changed the amount of renin present in the juxtaglomerular apparatus. In rats on a high salt intake the total renin was low and was all in an active form.

Generation of Inactive Renin in Vitro and in Vivo: Reversible Inactivation of the Active Plasma Enzyme in Rats

1982 ◽  
Vol 63 (s8) ◽  
pp. 171s-174s ◽  
Author(s):  
Jack D. Barrett ◽  
Peter Eggena ◽  
Mohinder P. Sambhi
Keyword(s):  
Active Form ◽  
Renin Angiotensin System ◽  
Active Plasma ◽  
Reversible Inactivation ◽  
Active Renin ◽  
Plasma Enzyme ◽  
Inactive Renin ◽  
Rate Of Decline

1. Active and total (trypsin treatment) plasma renins were measured in normal Wistar rats and in rats in which the renin-angiotensin system was stimulated by ether anaesthesia. 2. After incubation of normal plasma in vitro in the absence of angiotensinase inhibitors, active renin declined. This decline was shown to be due to the conversion of active renin into an inactive form, which could be re-activated by trypsin. 3. In plasma from renin-stimulated rats, the rate of decline of active renin in vitro was accelerated; however, the relative amount of inactive renin generated was decreased. 4. Ligation of the kidneys of the ether-anaesthetized animal resulted in a build-up in vivo of inactive renin concomitant with the decline of active renin. 5. These data demonstrate the conversion of active into inactive renin in vitro and indicate that inactive renin can also be generated in vivo from the active form of the enzyme. 6. Multiple forms of inactive renin may exist; some may be true ‘prorenins’ (renin zymogens) produced in the kidney, and others may result from post-biosynthetic modifications of the active plasma enzyme.

Absence of Activation in Vitro of Renin in Rat Plasma

1982 ◽  
Vol 62 (4) ◽  
pp. 435-437 ◽  
Author(s):  
M. H. De Keijzer ◽  
A. P. Provoost ◽  
F. H. M. Derkx
Keyword(s):  
Human Plasma ◽  
Active Form ◽  
Plasma Renin ◽  
Rat Plasma ◽  
Plasma Renin Concentration ◽  
Inactive Form ◽  
Inactive Renin

1. Rat plasma was subjected at 4°C to various treatments known to convert inactive renin into its active form in human plasma. 2. No statistical differences in plasma renin concentration were found when the levels after the various treatments were compared with that of untreated rat plasma. 3. It is concluded that, in contrast to human plasma, no inactive form of renin is present in rat plasma.

Two-Site Direct Immunoassay Specific for Active Renin

1992 ◽  
Vol 38 (10) ◽  
pp. 1959-1962 ◽  
Author(s):  
D Simon ◽  
D J Hartmann ◽  
G Badouaille ◽  
G Caillot ◽  
T T Guyenne ◽  
...  
Keyword(s):  
Magnetic Beads ◽  
Active Form ◽  
Plasma Renin ◽  
Active Plasma ◽  
Immunoradiometric Assay ◽  
Active Renin ◽  
Human Renin ◽  
Direct Immunoassay ◽  
Inactive Renin ◽  
Normotensive Subjects

Abstract A sensitive immunoradiometric assay, without an enzymatic step and specific for active human renin, was developed with use of two monoclonal antibodies (MAbs). In this assay system, the first MAb was coupled to magnetic beads (Magnogel); the second one, directed against the active form of the enzyme, was radiolabeled with 125I. The specificity of this assay was demonstrated in experiments measuring the active plasma renin concentration in the presence or absence of inactive renin. The assay, performed in two steps, was sensitive enough to detect 0.9 pg of renin per tube (3.5 ng/L). Intra- or interassay CVs were < 10%. Concentrations of active plasma renin measured in normotensive subjects were between 7 and 40 ng/L.

scholarly journals Salt-sensitive splice variant of nNOS expressed in the macula densa cells

2010 ◽  
Vol 298 (6) ◽  
pp. F1465-F1471 ◽  
Author(s):  
Deyin Lu ◽  
Yiling Fu ◽  
Arnaldo Lopez-Ruiz ◽  
Rui Zhang ◽  
Ramiro Juncos ◽  
...  
Keyword(s):  
Salt Intake ◽  
Splice Variants ◽  
Macula Densa ◽  
High Salt ◽  
Tubuloglomerular Feedback ◽  
No Production ◽  
Thick Ascending Limb ◽  
High Salt Diet ◽  
Salt Diet ◽  
High Salt Intake

Neuronal nitric oxide synthase (nNOS), which is abundantly expressed in the macula densa cells, attenuates tubuloglomerular feedback (TGF). We hypothesize that splice variants of nNOS are expressed in the macula densa, and nNOS-β is a salt-sensitive isoform that modulates TGF. Sprague-Dawley rats received a low-, normal-, or high-salt diet for 10 days and levels of the nNOS-α, nNOS-β, and nNOS-γ were measured in the macula densa cells isolated with laser capture microdissection. Three splice variants of nNOS, α-, β-, and γ-mRNAs, were detected in the macula densa cells. After 10 days of high-salt intake, nNOS-α decreased markedly, whereas nNOS-β increased two- to threefold in the macula densa measured with real-time PCR and in the renal cortex measured with Western blot. NO production in the macula densa was measured in the perfused thick ascending limb with an intact macula densa plaque with a fluorescent dye DAF-FM. When the tubular perfusate was switched from 10 to 80 mM NaCl, a maneuver to induce TGF, NO production by the macula densa was increased by 38 ± 3% in normal-salt rats and 52 ± 6% ( P < 0.05) in the high-salt group. We found 1) macula densa cells express nNOS-α, nNOS-β, and nNOS-γ, 2) a high-salt diet enhances nNOS-β, and 3) TGF-induced NO generation from macula densa is enhanced in high-salt diet possibly from nNOS-β. In conclusion, we found that the splice variants of nNOS expressed in macula densa cells were α-, β-, and γ-isoforms and propose that enhanced level of nNOS-β during high-salt intake may contribute to macula densa NO production and help attenuate TGF.

scholarly journals Stimulation of Epithelial Sodium Channels in Endothelial Cells by Bone Morphogenetic Protein-4 Contributes to Salt-Sensitive Hypertension in Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xu Yang ◽  
Na Niu ◽  
Chen Liang ◽  
Ming-Ming Wu ◽  
Liang-Liang Tang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Bone Morphogenetic Protein ◽  
Salt Intake ◽  
High Salt ◽  
Bone Morphogenetic Protein 4 ◽  
Sodium Influx ◽  
Morphogenetic Protein ◽  
High Salt Intake ◽  
Stimulation Of

Previous studies have shown that high salt induces artery stiffness by causing endothelial dysfunction via increased sodium influx. We used our unique split-open artery technique combined with protein biochemistry and in vitro measurement of vascular tone to test a hypothesis that bone morphogenetic protein 4 (BMP4) mediates high salt-induced loss of vascular relaxation by stimulating the epithelial sodium channel (ENaC) in endothelial cells. The data show that high salt intake increased BMP4 both in endothelial cells and in the serum and that exogenous BMP4 stimulated ENaC in endothelial cells. The data also show that the stimulation is mediated by p38 mitogen-activated protein kinases (p38 MAPK) and serum and glucocorticoid-regulated kinase 1 (Sgk1)/neural precursor cell expressed developmentally downregulated gene 4-2 (Nedd4-2) (Sgk1/Nedd4-2). Furthermore, BMP4 decreased mesenteric artery relaxation in a benzamil-sensitive manner. These results suggest that high salt intake stimulates endothelial cells to express and release BMP4 and that the released BMP4 reduces artery relaxation by stimulating ENaC in endothelial cells. Therefore, stimulation of ENaC in endothelial cells by BMP4 may serve as another pathway to participate in the complex mechanism of salt-sensitive (SS) hypertension.

Active and inactive renin in human forearm of hypertensive patients

1991 ◽  
Vol 69 (9) ◽  
pp. 1390-1393 ◽  
Author(s):  
Stefano Taddei ◽  
Stefania Favilla ◽  
Antonio Salvetti
Keyword(s):  
Brachial Artery ◽  
Vascular Tissue ◽  
Physiological Role ◽  
Renin Angiotensin System ◽  
Hypertensive Patients ◽  
Active Renin ◽  
Inactive Renin ◽  
Dose Dependent

Although many in vitro and animal studies indicate the existence of a local renin–angiotensin system, data regarding its physiological role are quite controversial, and moreover, evidence suggesting inactive and active renin release from vascular tissue in vivo is lacking both in animal and humans. The aim of our study was to evaluate whether β-adrenoceptor stimulation, a well-known stimulus to renin production, through isoproterenol might cause local renin production from vessels of the forearm of hypertensive patients. Drugs were infused into the brachial artery at systemically ineffective rates, while forearm blood flow (FBF, venous plethysmography), mean intra-arterial pressure, and heart rate were monitored throughout. Active and inactive vessel renin production was measured by calculating venous-arterial (V-A) differences by simultaneous sampling from brachial artery and an ipsilateral deep vein. Active renin (PRA) and total renin (Sepharose bound trypsin activation) were measured by radioimmunoassay while inactive renin was calculated as the difference between total and active renin. V-A differences were corrected for FBF to calculate renin extraction or production. In a group of 10 patients, isoproterenol, which was infused at increasing cumulative rates (0.03, 0.1, 0.3 μg∙100 mL−1 forearm tissue∙min−1 for 5 min each), caused a dose-dependent increment in FBF that was blunted by intra-arterial propranolol (n = 5) pretreatment (10 μg∙100 mL−1 forearm tissue∙min−1 for 10 min). β-Adrenoceptor stimulation caused a dose-dependent outflow of both active and inactive renin, an effect antagonized by propranolol. In conclusion, our data represent the first evidence in humans of tissue active and inactive renin production in the forearm vascular bed.Key words: tissue renin, active renin, inactive renin, isoproterenol.

Evidence for Activation of Circulating Inactive Renin by the Human Kidney

1979 ◽  
Vol 56 (2) ◽  
pp. 115-120 ◽  
Author(s):  
F. H. M. Derkx ◽  
G. J. Wenting ◽  
A. J. Man In't Veld ◽  
R. P. Verhoeven ◽  
M. A. D. H. Schalekamp
Keyword(s):  
Renal Vein ◽  
Human Kidney ◽  
Activation Process ◽  
Peripheral Vein ◽  
Active Renin ◽  
A Value ◽  
Before And After ◽  
Inactive Renin ◽  
Propranolol Treatment ◽  
Stimulation Of

1. In eight patients with essential hypertension (EHT) and six patients with renovascular hypertension (RVHT) peripheral venous enzymatically active and inactive renin values were followed after acute stimulation of renin release by the vasodilating agent diazoxide (300 mg intravenously). Active renin rose during the first hour after diazoxide and remained high during the following 15 h, but inactive renin fell during the first hour and rose thereafter. Peripheral venous active and inactive renin were not different from arterial values both before and after diazoxide. 2. Sixteen patients with EHT received propranolol, 80 mg, four times a day. Six of them had a first injection of diazoxide the day before propranolol was started and a second one after 10–14 days of propranolol treatment. Peripheral vein active renin was lowered by propranolol, but inactive renin was raised. Both the diazoxide-induced rapid rise of active renin and the fall of inactive renin observed in untreated patients were absent during treatment with propranolol. 3. In four patients with EHT and seven patients with RVHT renal vein sampling was performed before and 30 min after diazoxide. Increased release of active renin from kidneys that were not markedly contracted was associated with a fall of the renal vein to peripheral vein ratio of inactive renin to a value less than one. 4. It is concluded that under certain circumstances stimulated release of active renin is associated with removal of inactive renin from the circulation by the kidney. This may in fact be due to intrarenal transformation of circulating inactive renin into its active counterpart. The findings suggest that a β-adrenoreceptor might be involved in this activation process.

scholarly journals A new view of macula densa cell microanatomy

2021 ◽  
Author(s):  
Georgina Gyarmati ◽  
Urvi Nikhil Shroff ◽  
Anne D.M. Riquier-Brison ◽  
Wilhelm Kriz ◽  
Brigitte Kaissling ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Salt Intake ◽  
Macula Densa ◽  
Full Detail ◽  
Target Cells ◽  
Dynamic Features ◽  
Dietary Salt ◽  
Fixed Tissue

Although macula densa (MD) cells are chief regulatory cells in the nephron with unique microanatomical features, they have been difficult to study in full detail due to their inaccessibility and limitations in earlier microscopy techniques. The present study used a new mouse model with a comprehensive imaging approach to visualize so far unexplored microanatomical features of MD cells, their regulation and functional relevance. MD-GFP mice with conditional and partial induction of green fluorescent protein (GFP) expression, which specifically and intensely illuminated only single MD cells were used with fluorescence microscopy of fixed tissue and live MD cells in vitro and in vivo with complementary electron microscopy (EM) of rat, rabbit, and human kidney. An elaborate network of major and minor cell processes here named maculapodia were found at the cell base, projecting towards other MD cells and the glomerular vascular pole. The extent of maculapodia showed up-regulation by low dietary salt intake and female gender. Time-lapse imaging of maculapodia revealed highly dynamic features including rapid outgrowth and an extensive vesicular transport system. EM of rat, rabbit, and human kidneys, and three-dimensional (3D) volume reconstruction in optically cleared whole-mount MD-GFP mouse kidneys further confirmed the presence and projections of maculapodia into the extraglomerular mesangium and the afferent and efferent arterioles. The newly identified dynamic and secretory features of MD cells suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus (JGA) between MD cells and between MD and other target cells.

Plasma inactive renin in diabetic patients with neuropathy: a role for the sympathetic nervous system in the conversion in vivo of inactive renin

1983 ◽  
Vol 104 (2) ◽  
pp. 216-221 ◽  
Author(s):  
Mitsuaki Nakamaru ◽  
Toshio Ogihara ◽  
Jitsuo Higaki ◽  
Kazuko Masuo ◽  
Hiroshi Ikegami ◽  
...  
Keyword(s):  
Active Form ◽  
Plasma Norepinephrine ◽  
Diabetic Patients ◽  
Plasma Catecholamine ◽  
Active Renin ◽  
Significant Difference ◽  
Inactive Renin ◽  
The Mean ◽  
Group 2 ◽  
Group 1

Abstract. Plasma levels of active and trypsin-activatable inactive renin and catecholamines were measured in 6 diabetic patients with neuropathy (group 1), 8 diabetic patients without neuropathy (group 2) and 8 agematched normal subjects. The effect of insulin administration on plasma active and inactive renin and plasma catecholamine levels in diabetic patients was also investigated. The levels of inactive renin were calculated as the difference between the levels of total renin after trypsin activation and those of active renin. The levels of plasma catecholamines were determined by the trihydroxyindole method. The levels of active renin were significantly lower and inactive renin was increased slightly in group 1 when compared with controls. Group 1 showed a significant reduction in plasma norepinephrine levels. Group 2 showed slightly reduced active renin, normal inactive renin and normal norepinephrine values. There was no significant difference in the levels of epinephrine between the 3 groups. After insulin injection, active renin levels were increased in groups 1 and 2. The mean increment in active renin levels was less in group 1 than in group 2. Inactive renin levels were slightly decreased in both groups. Significant increases in epinephrine and norepinephrine levels were observed following insulin administraion. The mean increment in norepinephrine levels was less in group 1 than in group 2. There was a positive correlation between the mean increment in active renin and in norepinephrine levels in diabetic patients. These results suggest that the impaired conversion of inactive renin into an active form is responsible in part for the low levels of active renin in diabetics with neuropathy.

Ontogeny of isoproterenol-stimulated renin secretion from sheep renal cortical slices

1989 ◽  
Vol 256 (6) ◽  
pp. R1258-R1263
Author(s):  
K. T. Nakamura ◽  
W. V. Page ◽  
T. Sato ◽  
J. M. Klinkefus ◽  
J. E. Robillard
Keyword(s):  
Active Form ◽  
Age Groups ◽  
The Other ◽  
Renin Secretion ◽  
Base Line ◽  
Active Renin ◽  
Kidney Slices ◽  
Inactive Renin ◽  
Synthase Inhibitor ◽  
Cortical Slices

The ontogeny of renin secretion from renal cortical slices was studied in two groups of fetal (107-109 days of gestation and 131-136 days of gestation; term is 145 days), newborn (3-9 days old), and adult nonpregnant sheep. Isoproterenol (ISO; 10(-8)-10(-5) M) significantly increased active renin secretion in all age groups (P less than 0.05), with newborns having the highest values at all concentrations. However, the percent changes in active renin secretion were similar among all ages. Inactive renin secretion also increased with ISO stimulation, with newborns having the highest rate of inactive renin secretion. The percent of total renin in the active form differed among ages, ranging at base line from 60 +/- 10% in fetuses at greater than 130 days of gestation to 88 +/- 6% in fetuses at less than 110 days of gestation (P less than 0.05). Propranolol (1 microM) inhibited ISO (10(-6) M)-stimulated active renin secretion at all ages. On the other hand, the prostaglandin (PG) synthase inhibitor aspirin (1.6 x 10(-5) M) did not inhibit ISO (10(-6) M)-mediated increases in active renin secretion in fetal (greater than 130 days of gestation) kidney slices and produced values intermediate between base line and ISO alone in newborns and adults.(ABSTRACT TRUNCATED AT 250 WORDS)

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