scholarly journals Role of fibrinogen in the glomerular permeability of the perfused, isolated dog kidney

1985 ◽  
Vol 27 (5) ◽  
pp. 807-810 ◽  
Author(s):  
Marwan A. Masri ◽  
Nigel D. Boyd ◽  
Henry Mandin
Keyword(s):  
Glomerular Permeability ◽  
Dog Kidney ◽  
Isolated Dog Kidney

Diuretic and hemodynamic effects of furosemide in the isolated dog kidney

1973 ◽  
Vol 277 (1) ◽  
pp. 13-26 ◽  
Author(s):  
N. T. Stowe ◽  
L. F. Wolterink ◽  
A. E. Lewis ◽  
J. B. Hook
Keyword(s):  
Hemodynamic Effects ◽  
Dog Kidney ◽  
Isolated Dog Kidney

scholarly journals Effects of Several Androgens and Steroid Metabolites on Erythropoietin Production in the Isolated Perfused Dog Kidney

Blood ◽  
1974 ◽  
Vol 43 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Luiz G. Paulo ◽  
Gregory D. Fink ◽  
Byung L. Roh ◽  
James W. Fisher
Keyword(s):  
Double Bond ◽  
Spatial Configuration ◽  
Significant Elevation ◽  
Methyl Group ◽  
Erythropoietin Production ◽  
Dog Kidney ◽  
Isolated Kidneys

Abstract In an attempt to clarify the role of the kidney in the action of several androgens and steroid metabolites on erythropoietin (ESF) production, ESF titers were measured in perfusates of isolated kidneys from dogs previously exposed to 4-hr hypoxia and perfused with blood containing testosterone (Test), 5α-17β-hydroxyandrostan-3-one (5αDHT), 5β-17β-hydroxyandrostan-3-one (5βDHT), 19-nortestosterone (19-nor), oxymetholone (Oxy), fluoxymesterone (Fluoxy), 3α-hydroxy-5β-pregnane, 11,20-dione (3αOH5βpreg), or 3β-hydroxy-5β-pregnane-20-one (3βOH-5 preg). ESF levels in the perfusates were assayed in exhypoxic polycythemic mice. Test, 5αDHT, oxy, fluoxy, and 3βOH5β-preg were found to produce a significant increase in ESF levels in the kidney perfusates. 5βDHT, 19-nor, and 3αOH5βpreg failed to produce a significant elevation in erythropoietin titers in the perfusates of the isolated perfused kidneys. These data suggest that the 4-5 double bond and the spatial configuration of the hydrogen at the 5 position as well as the lack of a methyl group in the 19 position of the basic androstan nucleus are important in the ability of these steroids to stimulate kidney production of ESF.

Effect of an angiotensin II antagonist on autoregulation in the isolated dog kidney

1976 ◽  
Vol 230 (4) ◽  
pp. 1078-1083 ◽  
Author(s):  
GJ Kaloyanides ◽  
GF DiBona
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
Arterial Pressure ◽  
Flow Distribution ◽  
Renin Angiotensin System ◽  
Vascular Effects ◽  
Isolated Kidney ◽  
Angiotensin Ii Antagonist ◽  
Dog Kidney ◽  
Isolated Dog Kidney

The effect of the specific angiotensin II antagonist (AIIA), [1-sarcosine-8-alanine]angiotensin II, on autoregulation of glomerular filtration rate (GFR) and renal blood flow (RBF) in an isolated dog kidney was examined. Infusing the AIIA into the renal artery at 1.9 mug/min inhibited the renal vasoconstrictor action of angiotension II infused simultaneously at 1.15 mug/min. Under conditions of constant renal arterial pressure the AIIA had no significant effect on sodium excretion, GFR, RBF, cortical blood flow distribution (microsphere method), or renin secretion in non-renin-depleted kidneys. Similarly, no agonist properties were observed when the AIIA was infused into renin-depleted kidneys. This dose of the AIIA did not impair the capacity of the isolated kidney to regulate GFR or RBF when renal arterial pressure was increased from 100 to 150 mmHg. Efficiency of autoregulation of GFR and RBF was 77 and 82% of that predicted for perfect autoregulation. These values are not significantly different from those of the isolated kidney not infused with the antagonist. It is concluded that the angiotensin II antagonist, [1-sarcosine-8-alanine]angiotensin II, has no significant agonist properties, that it antagonizes the renal vascular effects of exogenously administered angiotensin II, but does not impair renal autoregulation. These data provide no support for the hypothesis that the renin-angiotensin system mediates the autoregulation of GFR and RBF.

Interactions between furosemide and vasopressin on hemodynamics and on water excretion by the isolated dog kidney

1976 ◽  
Vol 362 (3) ◽  
pp. 265-270 ◽  
Author(s):  
J. -L. Vanherweghem ◽  
J. Ducobu ◽  
A. D'hollander ◽  
C. Toussaint
Keyword(s):  
Water Excretion ◽  
Dog Kidney ◽  
Isolated Dog Kidney

Stretch reduces nephrin expression via an angiotensin II-AT1-dependent mechanism in human podocytes: effect of rosiglitazone

2010 ◽  
Vol 298 (2) ◽  
pp. F381-F390 ◽  
Author(s):  
Ilaria Miceli ◽  
Davina Burt ◽  
Elena Tarabra ◽  
Giovanni Camussi ◽  
Paolo Cavallo Perin ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Expression ◽  
Slit Diaphragm ◽  
Peroxisome Proliferator ◽  
Glomerular Permeability ◽  
Receptor System ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Mrna And Protein Expression

Increased glomerular permeability to proteins is a characteristic feature of diabetic nephropathy (DN). The slit diaphragm is the major restriction site to protein filtration, and the loss of nephrin, a key component of the slit diaphragm, has been demonstrated in both human and experimental DN. Both systemic and glomerular hypertension are believed to be important in the pathogenesis of DN. Human immortalized podocytes were subjected to repeated stretch-relaxation cycles by mechanical deformation with the use of a stress unit (10% elongation, 60 cycles/min) in the presence or absence of candesartan (1 μM), PD-123319 (1 μM), and rosiglitazone (0.1 μM). Nephrin mRNA and protein expression were assessed using quantitative real-time PCR, immunoblotting, and immunofluorescence, and the protein expression of AT1 receptor and angiotensin II secretion were evaluated. Exposure to stretch induced a significant ∼50% decrease in both nephrin mRNA and protein expression. This effect was mediated by an angiotensin II-AT1 mechanism. Indeed, podocyte stretching induced both angiotensin II secretion and AT1 receptor overexpression, podocyte exposure to angiotensin II reduced nephrin protein expression, and both the AT-1 receptor antagonist candesartan and a specific anti-angiotensin II antibody completely abolished stretch-induced nephrin downregulation. Similar to candesartan, the peroxisome proliferator-activated receptor (PPAR)-γ agonist, rosiglitazone, also inhibited stretch-induced nephrin downregulation, suggesting interference with stretch-induced activation of the angiotensin II-AT1 receptor system. Accordingly, rosiglitazone did not alter stretch-induced angiotensin II secretion, but it prevented AT1 upregulation in response to stretch. These results suggest a role for hemodynamic stress in loss of nephrin expression and allude to a role of PPAR-γ agonists in the prevention of this loss.

scholarly journals Role of endogenous CYP450 metabolites of arachidonic acid in maintaining the glomerular protein permeability barrier

2007 ◽  
Vol 293 (2) ◽  
pp. F501-F505 ◽  
Author(s):  
Jan Michael Williams ◽  
Mukut Sharma ◽  
Siddam Anjaiahh ◽  
John R. Falck ◽  
Richard J. Roman
Keyword(s):  
Arachidonic Acid ◽  
Essential Role ◽  
Dienoic Acid ◽  
Permeability Barrier ◽  
Selective Inhibitors ◽  
Glomerular Permeability ◽  
Isolated Glomeruli ◽  
Cytochrome P 450 ◽  
Protein Permeability

This study examined the metabolism of arachidonic acid (AA) by cytochrome P-450 enzymes in isolated glomeruli and the effects of selective inhibitors of the synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatetraenoic acids (EETs) on glomerular permeability to albumin ( Palb). Glomeruli avidly produced 20-HETE, EETs, dihydroxyeicosatetraenoic acids (diHETEs), and HETEs when incubated with exogenous AA. N-hydroxy- N′-(4-butyl-2-methylphenyl)formamidine (HET0016; 10 μM) selectively inhibited the formation of 20-HETE by 95% and increased Palb from 0.00 ± 0.08 to 0.73 ± 0.10 ( n = 43 glomeruli, 4 rats). Addition of a 20-HETE mimetic, 20-hydroxyeicosa-5( Z),14( Z)-dienoic acid (20-5,14-HEDE; 1 μM) opposed the effects of HET0016 (10 μM) to increase Palb (0.21 ± 0.10, n = 36 glomeruli, 4 rats). Preincubation of glomeruli with exogenous AA to increase basal production of 20-HETE had a similar effect. We also examined the effect of an epoxygenase inhibitor, N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MSPPOH; 5 μM), on Palb. MSPPOH (5 μM) significantly increased Palb but had no effect on the synthesis of EETs in glomeruli incubated with AA. However, MSPPOH (5 μM) selectively reduced epoxygenase activity by 50% in glomeruli incubated without added AA. Pretreatment with 8,9-EET (100 nM) attenuated the effects of MSPPOH (5 μM) on Palb. These results indicate that glomeruli produce 20-HETE, EETs, diHETEs, and HETEs and that endogenously formed 20-HETE and EETs play an essential role in the maintenance of the glomerular permeability barrier to albumin.

Ouabainlike factor in Milan hypertensive rats

1992 ◽  
Vol 263 (4) ◽  
pp. F739-F748 ◽  
Author(s):  
M. Ferrandi ◽  
E. Minotti ◽  
S. Salardi ◽  
M. Florio ◽  
G. Bianchi ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
High Performance ◽  
Direct Evidence ◽  
Calcium Atpase ◽  
Hypertensive Rats ◽  
Ouabain Binding ◽  
High Affinity ◽  
Genetically Hypertensive Rats ◽  
Dog Kidney

Ouabainlike factor (OLF) has been extracted from the hypothalamus and adrenals of the ox and rats of the Milan hypertensive strain (MHS) and their normotensive controls (MNS). OLF was identified by its ability to 1) inhibit ouabain-sensitive 86Rb uptake into human erythrocytes, 2) displace [3H]ouabain binding, and 3) inhibit purified dog kidney Na-K-adenosinetriphosphatase (ATPase). Rat and bovine OLF have similar characteristics. Those that are close to ouabain are 1) ligand conditions for maximal inhibitory activity, 2) high-performance liquid chromatography retention time, 3) reversibility of inhibitory activity on Na-K-ATPase, 4) reduced Na-K pump inhibitory activity by K, 5) high affinity for Na-K-ATPase, and 6) no activity on calcium ATPase. OLF does not resemble ouabain in the following characteristics: 1) the capacity of OLF to inhibit ouabain low-affinity Na-K-ATPase isoform is greater than that of ouabain and 2) the capacity of OLF to inhibit renal Na-K-ATPase isoforms is greater when the enzyme is obtained from adult rather than young rats. The yield of OLF is greater from MHS than MNS. These findings represent the first direct evidence that a higher amount of OLF is present in tissues from genetically hypertensive rats than from their inbred normotensive controls, maintained under the same dietary and environmental conditions. This further supports previous observations on the role of OLF in the pathogenesis of MHS hypertension.

Effects of Endotoxin on Hemodynamics of Isolated Dog Kidney

1987 ◽  
pp. 81-85 ◽  
Author(s):  
Nadine Bourgeois ◽  
Charles Reuse ◽  
Jean-Marie Boeynaems ◽  
Michel Staroukine ◽  
Jean-Louis Vanherweghem
Keyword(s):  
Dog Kidney ◽  
Isolated Dog Kidney
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