Modification of renin isoelectric heterogeneity in Goldblatt hypertensive rat

1985 ◽  
Vol 248 (6) ◽  
pp. E694-E698 ◽  
Author(s):  
F. M. Sessler ◽  
R. L. Malvin
Keyword(s):  
Isoelectric Focusing ◽  
Rat Kidney ◽  
Venous Blood ◽  
Renin Activity ◽  
Hypertensive Rat ◽  
Isoelectric Points ◽  
The Difference ◽  
Cortical Slices

Six forms of renin have been described in rat kidney. Different stimuli resulted in secretion of unique profiles of those forms. We studied their storage and secretion in the two-kidney, one-clip Goldblatt hypertensive rat (GHR). Renal venous blood, kidney homogenates, and incubation media from cortical slices were subjected to isoelectric focusing. In all samples tested, six peaks of renin activity were found with isoelectric points at pH 5.90, 5.70, 5.40, 5.20, 5.00, and 4.80. The quantity of renin activity for each form was expressed as a percentage of the total recovered from the gel. In control kidneys the profile of renin stored and that released by in vitro slices were similar. However, in plasma, the percentage of renin focusing at the more basic pH was decreased. This is in agreement with other work showing that the liver removes the more basic forms more rapidly than the acidic forms. The clipped kidney of GHR secreted, both in vivo and in vitro, a profile of renin forms that was significantly different from the control kidney. The difference was expressed by an increase in the secretion of the more acidic forms by the clipped kidney. It is hypothesized that changes in the secretory profile of renin may reflect changes in storage and synthesis of those forms.

Effect of tolbutamide on plasma renin activity.

1979 ◽  
Vol 236 (1) ◽  
pp. E1
Author(s):  
N K Sherma ◽  
V V Gossain ◽  
A M Michelakis ◽  
D R Rovner
Keyword(s):  
Cyclic Amp ◽  
Plasma Renin Activity ◽  
Biological Significance ◽  
Plasma Renin ◽  
Renin Activity ◽  
Control Group ◽  
Cortical Slices ◽  
Intact Rats

The effect of tolbutamide on renin secretion in rats was studied in vivo, and in vitro. Administration of tolbutamide in doses of 12.5 and 25 mg/kg body wt ip to two groups of rats produced no significant change in plasma renin activity compared to the control group. In the in vitro experiments renal cortical slices were incubated with increasing concentrations of tolbutamide (0--4 mg/ml). No significant increase in the net renin production was observed, whereas the concentration of cyclic AMP increased significantly in the incubation medium. These findings suggest that in the intact rats tolbutamide does not increase plasma renin activity. In the renal cortical experiments although tolbutamide increased cyclic AMP production, the increase may not have been sufficient to stimulate the net renin production. These results are of biological significance because of the possible effects of tolbutamide and increased plasma renin activity on the cardiovascular system.

Ammonia detoxification by the rat kidney in vivo

1978 ◽  
Vol 56 (5) ◽  
pp. 305-314 ◽  
Author(s):  
Patrick Vinay ◽  
Guy Lemieux ◽  
André Gougoux
Keyword(s):  
Glutamate Dehydrogenase ◽  
Time Course ◽  
Tissue Concentration ◽  
Rat Kidney ◽  
Venous Blood ◽  
Ammonia Concentration ◽  
Constant Infusion ◽  
Glutamine Concentration

The time course of changes in the concentration of metabolites in response to a nontoxic load of ammonia was measured in freeze-clamped kidneys of fasted rats. Following a single NH4HCO3 load, a decrease in tissue concentration of 2-oxoglutarate occurs but this change is small and delayed in relation to the peak of blood ammonia concentration. An immediate but transient increment in tissue glutamine also occurs. No close relationship between the mitochondrial free NAD:NADH ratio calculated from the glutamate dehydrogenase and the 3-hydroxybutyrate dehydrogenase systems is seen during alteration of ammonia concentration. In contrast with previously reported observations in the liver under similar circumstances, no increase in tissue or renal venous blood aspartate or alanine concentration occurs. A constant infusion of NH4HCO3 doubles the tissue glutamine concentration and changes net renal extraction of glutamine to net production. The infusion of NH4+ together with a carbon source (malate, lactate) results in similar increase in tissue and renal vein glutamine concentration. No accumulation of aspartate or alanine are seen. In vitro studies on isolated kidney tubules indicate that the net flux through both aspartate aminotransferase and glutamate dehydrogenase is dependent on the concentration of the reactants as expected for systems in near-equilibrium situation. It is concluded that the rat kidney response to an ammonia load differs from that of the liver despite the apparent existence of a similar network of near-equilibrium systems. Such a difference is best explained by renal glutamine synthesis and sequestration of glutamate as glutamine in vivo.

scholarly journals FACTORS INFLUENCING THE UPTAKE AND LOSS OF RADIOSULFATE BY RAT RENAL CORTICAL TISSUE IN VITRO

1957 ◽  
Vol 41 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Ingrith J. Deyrup
Keyword(s):  
Sulfur Metabolism ◽  
Rat Kidney ◽  
Metabolic Inhibitors ◽  
Renal Tubular Reabsorption ◽  
Renal Cortical Tissue ◽  
Renal Tubular ◽  
Free Media ◽  
Cortical Slices

Rat kidney cortical slices, during incubation in vitro, lose previously accumulated radiosulfur when exposed to conditions (e.g. addition to the medium of metabolic inhibitors) which normally depress the uptake of S35. The extent of this loss is not affected significantly by the presence of phlorhizin, an agent which enhances markedly radiosulfate accumulation. On the other hand, when tissues are chilled to 1°C., loss is slight or negligible even in the presence of metabolic inhibitors. These data, and observations on the effect of pre-incubation of kidney slices in S35-free media before the addition of radiosulfate, have been interpreted as evidence that S35 accumulation in vitro may be resolved into at least two processes, namely (a) entrance of the isotope-labelled anion into the cells, by diffusion and/or active transport, and (b) complexing of S35 (in ionic or other form) with an intracellular component. The postulated complex is stabilized, perhaps through inactivation of a specific enzyme, by chilling the tissue to 1°C. Possible relationships are discussed among the observations noted above, sulfur metabolism in general, and aspects of the known in vivo transport mechanism for sulfate ion; i.e., renal tubular reabsorption.

The Hierarchic Order of Intermediate Filament Structure and Assembly

1985 ◽  
Vol 43 ◽  
pp. 722-725
Author(s):  
U. Aebi ◽  
E.C. Glavaris ◽  
R. Eichner
Keyword(s):  
Tissue Specificity ◽  
Structural Model ◽  
Eukaryotic Cells ◽  
Cdna Sequencing ◽  
Filament Structure ◽  
Keratin Filaments ◽  
Isoelectric Points ◽  
Immunological Crossreactivity

Five different classes of intermediate-sized filaments (IFs) have been identified in differentiated eukaryotic cells: vimentin in mesenchymal cells, desmin in muscle cells, neurofilaments in nerve cells, glial filaments in glial cells and keratin filaments in epithelial cells. Despite their tissue specificity, all IFs share several common attributes, including immunological crossreactivity, similar morphology (e.g. about 10 nm diameter - hence ‘10-nm filaments’) and the ability to reassemble in vitro from denatured subunits into filaments virtually indistinguishable from those observed in vivo. Further more, despite their proteinchemical heterogeneity (their MWs range from 40 kDa to 200 kDa and their isoelectric points from about 5 to 8), protein and cDNA sequencing of several IF polypeptides (for refs, see 1,2) have provided the framework for a common structural model of all IF subunits.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Reliability of a Single β-Thromboglobulin Measurement in a Diabetic Population : Importance of PGE1 in Anticoagulant Mixture

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner
Keyword(s):  
In Vitro Release ◽  
Mean Value ◽  
Reliable Estimate ◽  
Diabetic Patients ◽  
Single Measurement ◽  
Diabetic Population ◽  
The Difference ◽  
Vitro Release

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

The procoagulant effects of factor V Leiden may be balanced against decreased levels of factor V and do not reflect in vivo thrombin formation in newborns

2006 ◽  
Vol 95 (03) ◽  
pp. 434-440 ◽  
Author(s):  
Satu Hyytiäinen ◽  
Ulla Wartiovaara-Kautto ◽  
Veli-Matti Ulander ◽  
Risto Kaaja ◽  
Markku Heikinheimo ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Platelet Rich Plasma ◽  
Venous Blood ◽  
Factor V Leiden ◽  
Factor V ◽  
Cord Plasma ◽  
Adult Plasma ◽  
Thrombin Formation

SummaryThrombin regulation in newborns remains incompletely understood.We studied tissue factor-initiated thrombin formation in cord plasma in vitro, and the effects of Factor VLeiden (FVL) heterozygosity on thrombin regulation both in vitro and in vivo in newborns. Pregnant women with known thrombophilia (n=27) were enrolled in the study. Cord blood and venous blood at the age of 14 days were collected from 11 FVL heterozygous newborns (FVL-positive) and from 16 FVL-negative newborns. Prothrombin fragment F1+2 and coagulation factors were measured. Tissue factor-initiated thrombin formation was studied in cord platelet-poor plasma (PPP) of FVL-negative and -positive newborns, and in both PPP and platelet-rich plasma (PRP) of healthy controls. The endogenous thrombin potential (ETP) in cord PPP or PRP was ∼60% of that in adult plasma, while thrombin formation started ∼55% and ∼40% earlier in cord PPP and PRP, respectively. Further, in FVL-positive newborns thrombin formation started significantly earlier than in FVL-negative newborns. Exogenous activated protein C (APC) decreased ETP significantly more in cord than in adult PRP. In FVL-negative cord plasma 5nM APC decreased ETP by 17.4±3.5% (mean±SEM) compared with only 3.5±3.8% in FVL-positive cord plasma (p=0.01). FVL-positive newborns showed similar levels of F1+2 but significantly decreased levels of factor V compared with FVL negative newborns both in cord plasma (FV 0.82±0.07 U/ml vs. 0.98±0.05 U/ml, p=0.03) and at the age of two weeks (FV 1.15±0.04 U/ml vs. 1.32±0.05 U/ml, p=0.03). In conclusion, newborn plasma showed more rapid thrombin formation and enhanced sensitivity to APC compared with adult plasma. FVL conveyed APC resistance and a procoagulant effect in newborn plasma. Lack of elevated F1+2 levels in FVL-positive infants, however, suggested the existence of balancing mechanisms; one could be the observed lower level of factor V in FVL heterozygous newborns.

scholarly journals Synaptopodin: An Actin-associated Protein in Telencephalic Dendrites and Renal Podocytes

1997 ◽  
Vol 139 (1) ◽  
pp. 193-204 ◽  
Author(s):  
Peter Mundel ◽  
Hans W. Heid ◽  
Thomas M. Mundel ◽  
Meike Krüger ◽  
Jochen Reiser ◽  
...  
Keyword(s):  
Dendritic Spines ◽  
Cultured Cells ◽  
Rat Kidney ◽  
Amino Acid Sequences ◽  
Cdna Clones ◽  
Globular Domain ◽  
Postnatal Maturation ◽  
Human And Mouse

Synaptopodin is an actin-associated protein of differentiated podocytes that also occurs as part of the actin cytoskeleton of postsynaptic densities (PSD) and associated dendritic spines in a subpopulation of exclusively telencephalic synapses. Amino acid sequences determined in purified rat kidney and forebrain synaptopodin and derived from human and mouse brain cDNA clones show no significant homology to any known protein. In particular, synaptopodin does not contain functional domains found in receptor-clustering PSD proteins. The open reading frame of synaptopodin encodes a polypeptide with a calculated Mr of 73.7 kD (human)/74.0 kD (mouse) and an isoelectric point of 9.38 (human)/9.27 (mouse). Synaptopodin contains a high amount of proline (∼20%) equally distributed along the protein, thus virtually excluding the formation of any globular domain. Sequence comparison between human and mouse synaptopodin revealed 84% identity at the protein level. In both brain and kidney, in vivo and in vitro, synaptopodin gene expression is differentiation dependent. During postnatal maturation of rat brain, synaptopodin is first detected by Western blot analysis at day 15 and reaches maximum expression in the adult animal. The exclusive synaptopodin synthesis in the telencephalon has been confirmed by in situ hybridization, where synaptopodin mRNA is only found in perikarya of the olfactory bulb, cerebral cortex, striatum, and hippocampus, i.e., the expression is restricted to areas of high synaptic plasticity. From these results and experiments with cultured cells we conclude that synaptopodin represents a novel kind of proline-rich, actin-associated protein that may play a role in modulating actin-based shape and motility of dendritic spines and podocyte foot processes.

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