Inactive Renin in Rabbit Plasma: Effect of Frusemide

1981 ◽  
Vol 60 (4) ◽  
pp. 393-398 ◽  
Author(s):  
H. K. Richards ◽  
D. J. Lush ◽  
A. R. Noble ◽  
K. A. Munday
Keyword(s):  
Plasma Levels ◽  
Time Course ◽  
Rabbit Plasma ◽  
Active Renin ◽  
Inactive Form ◽  
Plasma Active Renin ◽  
Inactive Renin ◽  
Time Courses ◽  
Induced Changes ◽  
Sodium And Potassium

1. An inactive form of renin exists in rabbit plasma. This can be activated, and therefore measured, after acidification (pH 2.8). 2. The effect of frusemide diuresis, with replacement of volume losses, on plasma levels of active and inactive renin was studied over a 3 1/2 h time course. Plasma active renin increased during frusemide diuresis but inactive renin disappeared from the circulation. The time courses for the changes in the two forms of renin were similar. 3. The peak of the frusemide-induced changes in renal function (urine flow, sodium and potassium excretion and creatinine clearance) preceded the maximum changes in the two forms of renin by 90 min. 4. The response of plasma levels of inactive renin to physiological stimuli depends on the nature of the stimulus, as well as its duration. Some form of sodium-sensitive mechanism may control the activation of inactive renin.

Stimulation of plasma inactive renin by dexamethasone in the cat

1989 ◽  
Vol 257 (6) ◽  
pp. E879-E884
Author(s):  
N. Glorioso ◽  
C. Troffa ◽  
G. Tonolo ◽  
M. G. Melis ◽  
P. Manunta ◽  
...  
Keyword(s):  
Time Course ◽  
Consensus Sequence ◽  
Recovery Period ◽  
Base Line ◽  
Active Renin ◽  
Human Renin ◽  
Inactive Form ◽  
Inactive Renin ◽  
Selective Increase ◽  
Stimulation Of

An inactive form of renin in human plasma is the biosynthetic precursor, prorenin. The cat is a good animal model for studies of inactive renin. The gene for human renin contains sequences homologous to the glucocorticoid consensus sequence. The response of cat plasma (active and inactive renin) and of angiotensinogen to administration of dexamethasone (0.5 mg/kg im, daily) was studied in ketamine-sedated cats (20 mg/kg im). Inactive renin increased by twofold after 7 days of dexamethasone (P less than 0.01). After a 7-day recovery period, it returned to base line. Active renin did not change. Angiotensinogen fell by 35% (P less than 0.01). The time course of the selective increase of plasma inactive renin showed that inactive renin began to rise after 2 days, peaking after 5 days. Ketamine alone induced inactive renin to rise slightly but significantly (P less than 0.05), although the magnitude of the increment was much less than that observed in ketamine-sedated cats receiving dexamethasone (P less than 0.01). Active renin did not change, whereas angiotensinogen was reduced by 25% (P less than 0.01). Our findings support the hypothesis that glucocorticoids might have a selective role in the synthesis and/or secretion of the precursor of renin, at least in the cat.

Inactive Renin in Rabbit Plasma: Effect of Haemorrhage

1979 ◽  
Vol 56 (2) ◽  
pp. 105-108 ◽  
Author(s):  
H. K. Richards ◽  
S. A. Grace ◽  
A. R. Noble ◽  
K. A. Munday
Keyword(s):  
Blood Vessels ◽  
Renin Activity ◽  
Bilateral Nephrectomy ◽  
Rabbit Plasma ◽  
Inactive Form ◽  
Inactive Renin ◽  
Plasma Effect

1. Renin activity in rabbit plasma increases after acidification (pH 3·3), probably due to activation of an inactive form of renin. 2. Both active and inactive renin in plasma increase after haemorrhage. This stimulus does not change the relative proportions of the two forms. 3. After ligation of the renal blood vessels neither form of renin increases in response to haemorrhage. 4. One day after bilateral nephrectomy no inactive renin could be demonstrated in plasma. 5. In the rabbit, therefore, the kidney is a major source of the inactive renin in plasma.

scholarly journals Light-Induced Changes in Photoreceptor Membrane Resistance and Potential in Gecko Retinas

1974 ◽  
Vol 64 (1) ◽  
pp. 26-48 ◽  
Author(s):  
L. H. Pinto ◽  
W. L. Pak
Keyword(s):  
Time Course ◽  
Membrane Conductance ◽  
Receptor Potential ◽  
Membrane Resistance ◽  
Photoreceptor Membrane ◽  
Membrane Hyperpolarization ◽  
Direct Measurements ◽  
Isolated Retina ◽  
Time Courses ◽  
Induced Changes

The time-course of the light-induced changes in membrane voltage and resistance were measured for single photoreceptors in the retina of Gekko gekko. In the surgically isolated retina, small stimuli directed toward the impaled receptor produced a membrane hyperpolarization the time-course of which was identical to that of the increase in membrane resistance. In the eyecup preparation nearly identical time-courses were evoked only after perfusion of the vitreous surface with solution having high (Mg++). Disparate time-courses were obtained in (a) the isolated retina when large or displaced stimuli were used, and (b) the eyecup preparation when it was treated normally (see Pinto and Pak. 1974. J. Gen. Physiol. 64:49) and when it was exposed to aspartate ions or hypoxia. These results are consistent with the hypothesis that the receptor potential (elicited in the impaled receptor as a result of quanta only it captures) is generated by a single ionic process that decreases membrane conductance. These measurements provide a means to distinguish the receptor potential from interactions. From direct measurements of membrane time constant and total resistance in darkness, total membrane capacitance was calculated. The mean capacitance was 7.1 x 10-5 µF. This high value is consistent with anatomical observations of membrane infoldings at the base of gecko photoreceptors.

Dog inactive renin: biochemical characterization and secretion into renal plasma and lymph

1986 ◽  
Vol 250 (1) ◽  
pp. E55-E61 ◽  
Author(s):  
V. J. Dzau ◽  
C. S. Wilcox ◽  
K. Sands ◽  
P. Dunckel
Keyword(s):  
Specific Antibody ◽  
Biochemical Characterization ◽  
Immunological Properties ◽  
Renal Lymph ◽  
Active Renin ◽  
Dog Plasma ◽  
Plasma Active Renin ◽  
Inactive Renin ◽  
Venous Plasma

It has been suggested that the dog is a useful model for studies of inactive renin (IR). However, the nature and origin of the trypsin-activated angiotensin-forming activity in dog plasma have not been fully defined. We characterized dog IR using renin-specific antibody, immunoaffinity, and Affigel blue chromatography. Activated IR resembles renal and plasma active renin in biochemical and immunological properties. IR was detected in renal lymph, arterial and venous plasma, as well as renal extracts. At basal state, there was a significant renal venous-arterial gradient of IR indicating secretion from the kidney. Furthermore, a sixfold higher concentration of IR was demonstrated in renal lymph than in plasma. Our data provides evidence for two possible routes of IR secretion from the kidney and supports the contention that the dog is a good model for studies of IR secretion and regulation.

Degradation of endogenous protein by rabbit pulmonary macrophages

1979 ◽  
Vol 47 (1) ◽  
pp. 79-86 ◽  
Author(s):  
K. H. Woodside ◽  
D. Massaro
Keyword(s):  
Amino Acids ◽  
Protein Degradation ◽  
Plasma Levels ◽  
Time Course ◽  
Polystyrene Latex ◽  
Rabbit Plasma ◽  
Exogenous Glucose ◽  
Endogenous Protein ◽  
Pulmonary Macrophages ◽  
Particle Attachment

Pulmonary macrophages were preincubated for 1 or 20 h with L-[U-14C]phenylalanine and the degradation of labeled proteins studied by reincubating these cells in the presence of 4 mM L-phenylalanine and measuring rates of [14C]phenylalanine released from the cells into the medium. We found that proteins prelabeled in 1 or 20 h were degraded 8.0 and 3.0%.h-1, respectively. Decreases in cell viability reduced the rate of protein degradation. Lack of exogenous glucose slowed the rate of degradation of proteins labeled in 1 h, but not of those labeled in 20 h. Varying amino acids in the medium from normal to 5 times normal rabbit plasma levels had no effect on the degradation of either group of proteins. Rates of degradation of both fast and slowly turning over proteins were inhibited during phagocytosis of polystyrene latex particles by about 62 and 33%, respectively. The time course of the changes in protein degradation suggests they are related to intracellular events in the phagocytic process, rather than particle attachment or uptake.

Isoprenaline-Induced Secretion of Active and Inactive Renin in Anaesthetized Rabbits and by Kidney Cortex Slices

1981 ◽  
Vol 61 (6) ◽  
pp. 679-684 ◽  
Author(s):  
H. K. Richards ◽  
A. R. Noble ◽  
K. A. Munday
Keyword(s):  
Time Course ◽  
Urine Volume ◽  
Renin Release ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Active Renin ◽  
Arterial Blood ◽  
Inactive Renin ◽  
Cortex Slices ◽  
Kidney Cortex Slices

1. The effect of the β-adrenoceptor agonist isoprenaline on the secretion of active and inactive renin was investigated in two preparations. 2. in ten urethane-anaesthetized rabbits isoprenaline, given as a renal artery infusion, had relatively minor effects on renal sodium excretion (increased) and systemic arterial blood pressure (decreased). Urine volume, potassium excretion, creatinine clearance and serum electrolytes were all unchanged. Plasma active and inactive renin both increased immediately and returned to basal values after ceasing the isoprenaline infusion. 3. No significant changes in either plasma renin activity or renal function were observed in a group of ten control animals. 4. The magnitude of the isoprenaline-induced changes in plasma active renin was similar to that in a previous study of frusemide diuresis, but the time course was quite different. Inactive renin disappeared from plasma during frusemide diuresis. 5. Renin release by rabbit kidney cortex slices was also studied. Isoprenaline, added to the incubation medium, caused a dose-related increase in active renin secretion, but inactive renin release remained unchanged. This is in marked constrast to a previous study where reducing [Na+] increased active renin and inhibited inactive renin output. 6. These data support our previous suggestion that activation of inactive renin is regulated by a sodium-sensitive intrarenal mechanism.

Biochemical characteristics of human renin expressed in transgenic mice

1993 ◽  
Vol 84 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Kazuo Takaori ◽  
Shokei Kim ◽  
Akiyoshi Fukamizu ◽  
Masashi Sagara ◽  
Masayuki Hosoi ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Plasma Concentrations ◽  
Biochemical Properties ◽  
Enzymic Activity ◽  
Mrna Levels ◽  
Active Renin ◽  
Human Renin ◽  
Inactive Form ◽  
Renin Mrna ◽  
Inactive Renin

1. Biochemical properties of human renin expressed in transgenic mice (hRN8-12 mice) carrying the human renin gene (Fukamizu et al. Biochem Biophys Res Commun 1989; 165: 826–32) were examined. The optimum pH of the enzymic activity against human angiotensinogen was 5.5 for both plasma and renal human renin in the hRN8-12 mice. Plasma concentrations of human active and inactive renin in the plasma of hRN8-12 mice were 16.7 ± 2.8 and 79.9 ± 14.0 pmol of angiotensin 1 h−1 ml−1, respectively, thereby indicating that the predominant form of plasma human renin is the inactive form, as is the case in humans. 2. The molecular masses of plasma human active and inactive renin and renal human active renin in the hRN8-12 mice were estimated to be 46kDa, 48kDa and 44kDa, respectively, as determined by h.p.l.c. on G3,000SW. 3. Human renin in the hRN8-12 mouse kidney was bound to a concanavalin A-Sepharose column, and was eluted with α-methyl-d-mannoside, showing that this renin is glycosylated, as is native human renin. 4. Low sodium treatment of the hRN8-12 mice for 2 weeks increased plasma human active renin, renal human renin and renal human renin mRNA levels by 2.6-, 3.8- and 2.8-fold, respectively. Thus, the biosynthesis and secretion of renal human renin in these transgenic mice are obviously stimulated by sodium depletion.

A Novel Chimaeric Derivative of Saruplase, rscu-PA-40kDA/Hir, Binds to Thrombin and Exerts Thrombus-specific Fibrinolysis in Arterial and Venous Thrombosis in Dogs

1997 ◽  
Vol 77 (03) ◽  
pp. 535-539 ◽  
Author(s):  
J Schneider ◽  
R Hauser ◽  
H-H Hennies ◽  
J Korioth ◽  
G Steffens ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Plasma Levels ◽  
Time Course ◽  
Bolus Injection ◽  
Specific Activity ◽  
Intravenous Bolus ◽  
Protease Domain ◽  
Parent Molecule ◽  
Significant Prolongation ◽  
Inhibitory Domain

SummaryThe chimaeric molecule rscu-PA-40kDA/Hir (M23) comprises the kringle and protease domain of saruplase (rscu-PA) and a thrombin inhibitory domain fused to the C-terminus of the protease domain. The 27 amino acid long thrombin inhibitory domain contains a sequence directed to the active site of thrombin and a fragment from the C-terminal region of hirudin. 125I-radiolabelled M23 (0.03 µM) bound to thrombin that was immobilised onto CNBr-activated sepharose beads. Unlabelled M23 (0.01-10 |xM) and hirudin (0.001-10 µµM) concentra-tion-dependently displaced 125I-M23 from its binding to thrombin. Saruplase (up to 10 (iM) did not influence the thrombin binding of M23. The fibrinolytic properties of M23 and saruplase were compared in anaesthetized dogs with femoral artery and saphenous vein thrombosis. Under concomitant heparinization, the intravenous bolus injections of 1 mg/kg M23 or saruplase induced reperfusion of thrombotically occluded femoral arteries in 4 out of 5 treated animals in each case. There was one reocclusion in the M23-treated group. Time to reperfusion (23 ± 4 vs 25 ± 11 min) and maximal height of reperfusion blood flow (98 ± 21 vs 108 ± 15 % of baseline flow) did not differ significantly between the treatment groups. The time course of the lysis of incorporated 125I-fibrin radioactivity in thrombosed saphenous veins was similar after bolus injections of M23 and saruplase. The maximal dissolution of 125I-fibrin in the venous thrombosis model was 91 ± 1 % in M23-and 88 ± 5 % in saruplase-treated animals. Plasma levels of fibrinogen were not influenced and a2-antiplasmin levels were slightly reduced (-27 ± 3 %) after bolus injection of M23. In contrast, bolus injection of saruplase was accompanied by a significant decrease of fibrinogen (-55 ± 19 %) and a2-antiplasmin (-75 ±11%) plasma levels. Template bleeding times virtually did not differ before (2.8 ± 0.3 min) and 60 min after bolus injection of M23 (3.1 ± 0.3 min), whereas treatment with saruplase resulted in a significant prolongation of template bleeding time from 2.6 ± 0.2 min to 28 ± 13 min. It is concluded that the saruplase derivative M23, while inducing equieffective thrombolysis after intravenous bolus injection in dogs, causes much fewer haemostatic side effects than its parent molecule. The high thrombus-specific activity of M23 is tentatively attributed to its affinity to clot-bound thrombin.

Ontogeny of neuronally released norepinephrine on renin secretion in sheep

1989 ◽  
Vol 257 (4) ◽  
pp. R765-R770 ◽  
Author(s):  
K. T. Nakamura ◽  
J. M. Klinkefus ◽  
F. G. Smith ◽  
T. Sato ◽  
J. E. Robillard
Keyword(s):  
Renin Secretion ◽  
Renal Nerves ◽  
Nerve Terminals ◽  
Norepinephrine Release ◽  
Fetal Sheep ◽  
Postnatal Maturation ◽  
Active Renin ◽  
Inactive Renin ◽  
Cortical Slices

The role of renal nerves and norepinephrine release on renin secretion during fetal and postnatal maturation has not been studied. Experiments were performed to determine the effect of veratridine, a substance known to promote norepinephrine release from nerve terminals, on active and inactive renin secretion from renal cortical slices of fetal (134-138 days gestation; term is 145 days), newborn (4-9 days of age), and adult nonpregnant sheep. Veratridine (10-300 microM) significantly increased active renin secretion and produced a small but nonsignificant rise in inactive renin secretion in all three groups of animals (P less than 0.05). The percent rise in active renin secretion during veratridine stimulation was similar among all groups. Veratridine-stimulated (300 microM) active renin secretion was antagonized by tetrodotoxin (0.5 and 5.0 microM) and DL-propranolol (1 microM) in fetal renal cortical slices. However, neither tetrodotoxin nor propranolol completely inhibited the stimulatory effect of veratridine on active renin secretion. These results suggest that 1) norepinephrine released from nerve terminals may regulate active renin secretion early during development; 2) the effect of veratridine on active renin secretion was similar in fetal, newborn, and adult sheep; 3) veratridine had no significant effect on inactive renin secretion; and 4) active renin secretion due to depolarization of nerve terminals in fetal sheep is dependent on activation of beta-adrenoceptors as it is in adults.

scholarly journals Chronic Stress-Induced Changes in Pro-Inflammatory Cytokines and Spinal Glia Markers in the Rat: A Time Course Study

2012 ◽  
Vol 19 (6) ◽  
pp. 367-376 ◽  
Author(s):  
Viktoriya Golovatscka ◽  
Helena Ennes ◽  
Emeran A. Mayer ◽  
Sylvie Bradesi
Keyword(s):  
Chronic Stress ◽  
Inflammatory Cytokines ◽  
Time Course ◽  
Time Course Study ◽  
Induced Changes ◽  
Pro Inflammatory Cytokines
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