RENIN LEVELS IN THE KANGAROO, THE WOMBAT AND OTHER MARSUPIAL SPECIES

1971 ◽  
Vol 51 (1) ◽  
pp. 79-90 ◽  
Author(s):  
PAMELA A. SIMPSON ◽  
J. R. BLAIR-WEST
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Angiotensin I ◽  
Renin Substrate ◽  
Angiotensin System ◽  
Plasma Renin Concentration ◽  
Red Kangaroo ◽  
Grey Kangaroo ◽  
Common Wombat ◽  
Marsupial Species

SUMMARY A renin—angiotensin system was shown to be present in several marsupial species in plasma and homogenates of the renal cortex. Species studied were: Eastern Grey kangaroo (Macropus giganteus), Red kangaroo (Megaleia rufa), common wombat (Vombatus hirsutus), pademelon (Thylogale billardierii), Bennett's wallaby (Wallabia rufogrisea frutica), a quokka (Setonix brachyurus) and a tiger cat (Dasyurus maculatus). Renin-substrate was found in the plasma of the Eastern Grey kangaroo, the Red kangaroo and the wombat. Renin was shown to be present in the plasma of all species by incubation alone or with heterologous marsupial renin-substrate. Plasma renin concentration and renal renin content were estimated by an established method using standard sheep renin-substrate. Plasma renin concentration was high, suggesting that marsupial renins have a high affinity for sheep substrate; renal renin estimates were low relative to eutherian species, suggesting that renal storage may be small. Plasma renin concentration and renal renin levels were proportionately related. Renin levels were consistently lowest in the wombat. Bilateral nephrectomy of an Eastern Grey kangaroo reduced plasma renin concentration to zero and increased renin-substrate concentration eightfold. The angiotensin-like incubation product from Eastern Grey kangaroo renin-substrate did not cross react with antibodies to [5-Ile]-angiotensin I, suggesting that the product has a different sequence of amino acids.

Methods for serial study of renin-angiotensin system in the unanesthetized rat

1975 ◽  
Vol 228 (2) ◽  
pp. 369-375 ◽  
Author(s):  
JS Carvalho ◽  
R Shapiro ◽  
P Hopper ◽  
LB Page
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Rat Plasma ◽  
Angiotensin I ◽  
Ether Anesthesia ◽  
Renin Substrate ◽  
Angiotensin System ◽  
Arterial Blood ◽  
Sympathetic Nervous ◽  
Improved Technique

Micromethods for measurement of plasma renin concentration (PRC) and plasma renin-substrate concentration (PSC) have been developed for rat plasma with radioimmunoassay of angiotensin I. An improved technique for aortic implantation of plastic cannulas was developed for use in experiments 1-2 wk in duration. The effects on components of renin system of anesthesia and tail cutting were studied. Arterial blood was sampled through cannulas without animal manipulation. PRC varied little in unanesthetized rats, was moderately and variably increased during pentobarbital anesthesia, and was markedly and consistently elevated during ether anesthesia. PSC was unchanged during anesthesia. PRC was increased in blood obtained by tail cutting within 1-2 min after cutting. With the use of the methods and techniques described here serial studies of the renin system in plasma of unanesthetized rats are shown to be feasible. A role for the sympathetic nervous system in the mediation of renin secretion by ether is proposed.

scholarly journals Quantification of intact plasma AGT consisting of oxidized and reduced conformations using a modified ELISA

2016 ◽  
Vol 311 (6) ◽  
pp. F1211-F1216 ◽  
Author(s):  
Ryousuke Satou ◽  
Hiroyuki Kobori ◽  
Akemi Katsurada ◽  
Kayoko Miyata ◽  
L. Gabriel Navar
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Rat Plasma ◽  
Limiting Factor ◽  
Angiotensin I ◽  
Renin Substrate ◽  
Angiotensin System ◽  
Mouse Plasma ◽  
Rats And Mice ◽  
Pleiotropic Actions

The pleiotropic actions of the renin-angiotensin system (RAS) depend on the availability of angiotensinogen (AGT) which generates angiotensin I (ANG I) when cleaved by renin. Thus, quantification of the intact AGT (iAGT) concentrations is important to evaluate the actual renin substrate available. The iAGT conformation exists as oxidized AGT (oxi-AGT) and reduced AGT (red-AGT) in a disulfide bond, and oxi-AGT has a higher affinity for renin, which may exacerbate RAS-associated diseases. Accordingly, we determined iAGT, oxi-AGT, and red-AGT levels in plasma from rats and mice. Blood samples were obtained by cardiac puncture and then immediately mixed with an inhibitor solution containing a renin inhibitor. Total AGT (tAGT) levels were measured by tAGT ELISA which detects both cleaved and iAGT. iAGT levels were determined by iAGT ELISA which was found to only detect red-AGT. Thus, it was necessary to treat samples with dithiothreitol, a reducing agent, to quantify total iAGT concentration. tAGT levels in rat and mouse plasma were 1,839 ± 139 and 1,082 ± 77 ng/ml, respectively. iAGT levels were 53% of tAGT in rat plasma but only 22% in mouse plasma, probably reflecting the greater plasma renin activity in mice. The ratios of oxi-AGT and red-AGT were ∼4:1 (rat) and 16:1 (mouse). Plasma iAGT consists of oxi-AGT and red-AGT, suggesting that oxidative stress can influence ANG I generation by the AGT conformation switch. Furthermore, the lower availability of plasma iAGT in mice suggests that it may serve as a limiting factor in ANG I formation in this species.

ESTIMATION OF MARSUPIAL RENIN USING MARSUPIAL RENIN-SUBSTRATE

1972 ◽  
Vol 53 (1) ◽  
pp. 125-130 ◽  
Author(s):  
PAMELA A. SIMPSON ◽  
J. R. BLAIR-WEST
Keyword(s):  
Substrate Concentration ◽  
Structural Difference ◽  
Plasma Renin ◽  
Angiotensin I ◽  
Ph Optimum ◽  
Ph Profile ◽  
Renin Substrate ◽  
Grey Kangaroo ◽  
Rate Of Reaction ◽  
Highly Correlated

SUMMARY Bilateral nephrectomy of an Eastern Grey kangaroo (Macropus giganteus) increased plasma renin-substrate concentration approximately tenfold when compared with intact kangaroos. A preparation made from this plasma had a renin-substrate concentration of 3000 ng/ml. A pH profile of rate of reaction with pig renin had an optimum at pH 5·39. By comparison, the pH optimum of sheep renin-substrate was pH 6·15. Estimates of plasma renin concentration for kangaroos, wombats and wallabies, using kangaroo renin-substrate or sheep renin-substrate were highly correlated. Results from incubation with sheep renin-substrate were greater and hence indicate the advantage in using this substrate for marsupial renin estimation. The consistently large difference between sheep and kangaroo renin-substrate when incubated with renin from marsupial and eutherian species appears to be due to a structural difference between the two substrates, probably near the C-terminal end of the angiotensin I molecule.

Postnatal development of the renin-angiotensin system in rats

1980 ◽  
Vol 238 (5) ◽  
pp. R432-R437 ◽  
Author(s):  
K. B. Wallace ◽  
J. B. Hook ◽  
M. D. Bailie
Keyword(s):  
Steady State ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Rat Plasma ◽  
Neonatal Rat ◽  
Postnatal Life ◽  
Renin Substrate ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Age Related

The purpose of this investigation was to correlate the development of the various enzyme activities associated with the renin-angiotensin system with age-related differences in the steady-state concentrations of angiotensin I (AI) and II (AII). Angiotensin was quantified by radioimmunoassay. Plasma renin activity and concentration increased between birth and 3 wk of age, and declined thereafter to adult values. Renal renin content, on the other hand, increased throughout the first 6 wk of postnatal life. The concentration of AII in plasma also increased following birth; however, maximum concentrations were not attained until 5 wk of age. In contrast, plasma AI did not increase between 3 and 6 wk of age. These data suggest that the steady-state concentration of AII in neonatal rat plasma may be partially limited by the low plasma renin substrate concentration. The increase in AII between 3 and 6 wk of age may reflect the increasing converting enzyme activity.

Longitudinal study of platelet angiotensin II binding in human pregnancy

1992 ◽  
Vol 82 (4) ◽  
pp. 377-381 ◽  
Author(s):  
Philip N. Baker ◽  
Fiona Broughton Pipkin ◽  
E. Malcolm Symonds
Keyword(s):  
Longitudinal Study ◽  
Angiotensin Ii ◽  
Post Partum ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Significant Rise ◽  
Renin Substrate ◽  
Plasma Renin Concentration ◽  
Plasma Angiotensin ◽  
In Pregnancy

1. Platelet angiotensin II binding, circulating angiotensin II levels, plasma renin substrate and plasma renin concentration were measured in a longitudinal study of 30 women during pregnancy and the puerperium. 2. There was a significant fall in platelet angiotensin II binding from 11 weeks gestation to 18 weeks gestation (P < 0.01). There were no further significant changes in platelet angiotensin II binding until after delivery, a significant rise in platelet angiotensin II binding being found at 6 weeks post partum as compared with at 36 weeks gestation (P < 0.01). There was no further significant change from 6 to 12 weeks post partum, and platelet angiotensin II binding at 6 and 12 weeks post partum in the pregnant cohort approximated to that in non-pregnant women. These changes parallel those known to occur in pressor responsiveness to angiotensin II in pregnancy. 3. Plasma angiotensin II concentration, plasma renin substrate and plasma renin concentration were all significantly higher during pregnancy than in the puerperium (P < 0.001). There were no significant changes during pregnancy in plasma angiotensin II concentration or plasma renin concentration, although plasma renin substrate rose throughout. 4. Significant inverse correlations between platelet angiotensin II binding and plasma angiotensin II concentration (P < 0.01), plasma renin substrate (P < 0.01) and plasma renin concentration (P 0>001) were found during pregnancy. These data suggest that down-regulation of platelet angiotensin II binding by the components of the renin-angiotensin system pertains in pregnancy. 5. We are currently investigating parallelism between platelet and vascular angiotensin-binding sites. If such is confirmed, studies of platelet angiotensin II binding in pregnancy may be of both basic physiological and clinical interest in relation to the hypertensive diseases of pregnancy.

Renin-angiotensin system in hypothyroid rats: effects of potassium iodide and triiodo-L-thyronine

1984 ◽  
Vol 105 (4) ◽  
pp. 505-510 ◽  
Author(s):  
E. Jiménez ◽  
M. Montiel ◽  
J. A. Narváez ◽  
M. Morell
Keyword(s):  
Plasma Renin Activity ◽  
Potassium Iodide ◽  
Renin Angiotensin System ◽  
Kinetic Studies ◽  
Plasma Renin ◽  
The Other ◽  
Renin Substrate ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Previously Treated

Abstract. Kinetic studies of the renin-angiotensin system (RAS) were carried out by measuring plasma renin activity (PRA), plasma renin concentration (PRC) and plasma renin substrate (PRS). Changes in this system were studied during hypothyroidism, after administration of propylthiouracil (PTU), and in thyroidectomized rats. A significant decrease in PRA and PRC was observed in those animals previously treated with PTU. However, a significant increase in PRC, and a decrease in PRS, were found in T animals, but no changes in PRA were observed. In these animals, after daily administration of potassium iodide for I week (T+KI), no changes in RAS were observed in comparison with T rats. Nevertheless, administration of daily doses of triiodo-ithyronine (T+T3) induced a significant increase in PRA, leaving PRC unaltered. In this case the changes in PRA were related to the increase in PRS after T3 treatment. These results suggest that two different mechanisms were involved in renin release, one activated in T rats and the other in pharmacological hypothyroidism.

Studies on the human ovarian renin-angiotensin system: optimization of assay methodology and effects of follicular stimulants

1990 ◽  
Vol 127 (3) ◽  
pp. 513-521 ◽  
Author(s):  
J. M. Brameld ◽  
F. Broughton Pipkin ◽  
E. M. Symonds
Keyword(s):  
Follicular Fluid ◽  
Ovarian Stimulation ◽  
Clomiphene Citrate ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
System Optimization ◽  
Renin Substrate ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Substrate Concentrations

ABSTRACT The renal and genital tracts share a common embryological origin; it is thus not surprising that tissues from both can synthesize renin. Preliminary studies showed extremely high concentrations of renin in follicular fluid (FRC) following ovarian stimulation for in-vitro fertilization. This necessitated complete revalidation of the renin assays and showed that data obtained using commercial kits were invalid. An assay protocol was developed using a 1:2 dilution of follicular fluid taken into EDTA (0·3 mol/l) and o-phenanthroline (0·05 mol/l). The assay was performed at pH 7·5 in the presence of excess exogenous (sheep) renin substrate, with incubation periods of 5, 10 and 15 min at 37 °C. This protocol resulted in the linear generation of angiotensin I (AI). Activation of inactive renin was performed using eightfold more trypsin than was required for plasma samples. Follicular renin substrate concentrations (FRS) were measured using the same assay methodology as used for measurement of plasma renin substrate concentrations (PRS). Storage of samples at −18 °C for up to 2 months was found not to affect the FRC, although repeated freeze-thaw cycles did. FRC and plasma renin concentrations (PRC) were very similar in 25 unstimulated control women, studied in the follicular phase of the menstrual cycle. Trypsin activation increased follicular total renin concentration (FTRC) more than plasma total renin concentration (PTRC) (P< 0·0001). FRS was slightly higher than PRS (P<0·02). Ovarian stimulation with clomiphene citrate (CC; six women) was without effect on these parameters. However, hyperstimulation with CC, human menopausal gonadotrophins (hMG) and human chorionic gonadotrophin (hCG) resulted in substantial increments in FRC and FTRC (P< 0·0001 for both) and somewhat smaller rises in PRC and PTRC (P<0·05; P < 0·0005). There was also a small rise in PRS (P< 0·0002), but no change in FRS. Treatment with buserelin, hMG and hCG was associated with similarly large increases in renin concentrations, and also increases in both FRS and PRS (P< 0·003; P<0·007) in comparison with samples from women stimulated with CC, hMG and hCG. Increased plasma renin activity has previously been reported in stimulated ovarian follicular fluid. Our data show clearly that this is primarily due to a rise in FRC and FTRC and not to a rise in FRS. The use of the anti-oestrogen CC alone for ovarian stimulation was without effect on the follicular renin-angiotensin system. Thus we suggest that it is the gonadotrophins themselves which stimulate renin production, presumably by the theca cells. The much smaller rise in PRC and PTRC may reflect the effects of an overspill into the systemic circulation or, less likely, effects of the gonadotrophins on renal renin production. There is no evidence for this latter suggestion. FRS was increased only slightly by ovarian stimulation and must be presumed to be rate-limiting in the generation of AI. Journal of Endocrinology (1990) 127, 513–521

scholarly journals Sustained Dysregulation of the Plasma Renin-angiotensin System in Acute COVID-19

2021 ◽  
Author(s):  
Kevin Burns ◽  
Matthew Cheng ◽  
Todd Lee ◽  
Allison McGeer ◽  
David Sweet ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Converting Enzyme ◽  
Angiotensin I ◽  
Clinical Trial Registration ◽  
Angiotensin System ◽  
Angiotensin Converting Enzyme 2 ◽  
Renin Angiotensin ◽  
Plasma Angiotensin

Abstract SARS-CoV-2 enters cells by binding to angiotensin-converting enzyme 2 (ACE2), and COVID-19 infection may therefore induce changes in the renin-angiotensin system (RAS). To determine the effects of COVID-19 on plasma RAS components, we measured plasma ACE, ACE2, and angiotensins I, (1-7), and II in 46 adults with COVID-19 at hospital admission and on days 2, 4, 7 and 14, compared to 50 blood donors (controls). We compared survivors vs. non-survivors, males vs. females, ventilated vs. not ventilated, and angiotensin receptor blocker (ARB) and angiotensin-converting enzyme (ACE) inhibitor-exposed vs. not exposed. At admission, COVID-19 patients had higher plasma levels of ACE (p=0.012), ACE2 (p=0.001) and angiotensin-(1-7) (p<0.001) than controls. Plasma ACE and ACE2 remained elevated for 14 days in COVID-19 patients, while plasma angiotensin-(1-7) decreased after 7 days. In adjusted analyses, plasma ACE was higher in males vs. females (p=0.042), and plasma angiotensin I was significantly lower in ventilated vs. non-ventilated patients (p=0.001). In summary, plasma ACE and ACE2 are increased for at least 14 days in patients with COVID-19 infection. Angiotensin-(1-7) levels are also elevated, but decline after 7 days. The results indicate dysregulation of the RAS with COVID-19, with increased circulating ACE2 throughout the course of infection.Clinical Trial Registration: https://clinicaltrials.gov/ Unique Identifier: NCT04510623

The Sympathetic Nervous System and the Renin-Angiotensin System in Borderline Hypertension

1981 ◽  
Vol 60 (1) ◽  
pp. 25-31 ◽  
Author(s):  
J. W. Henquet ◽  
T. Kho ◽  
M. Schols ◽  
H. Thijssen ◽  
K. H. Rahn
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Concentrations ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Plasma Catecholamine ◽  
Bicycle Ergometry ◽  
Angiotensin System ◽  
Plasma Renin Concentration ◽  
Borderline Hypertension

1. Plasma catecholamine levels as well as plasma renin activity and plasma renin concentration were compared in normotensive volunteers and in subjects with borderline hypertension. All subjects were studied at rest and during bicycle ergometry. 2. The two groups of volunteer subjects did not differ in the plasma concentrations of noradrenaline and adrenaline, both at rest and during physical activity. The same was true for plasma renin activity and plasma renin concentration. Furthermore, urinary excretion of noradrenaline, adrenaline and 4-hydroxy-3-methoxymandelic acid was similar in both groups. 3. The results do not support the assumption that there is increased sympathetic activity in subjects with borderline hypertension.

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