Biochemical and immunological differences between plasma inactive renin from normal and nephrectomized rats

1991 ◽  
Vol 69 (9) ◽  
pp. 1350-1354 ◽  
Author(s):  
Shokei Kim ◽  
Masayuki Hosoi ◽  
Kiichiro Nakajima ◽  
Kenjiro Yamamoto
Keyword(s):  
Molecular Weight ◽  
Hplc Analysis ◽  
Rat Plasma ◽  
The Other ◽  
Trypsin Treatment ◽  
Angiotensin I ◽  
Active Renin ◽  
Normal Rat ◽  
Inactive Renin

Using immunological techniques, we have demonstrated that about half the trypsin-activatable renin in normal rat plasma is prorenin, while the other is not, and that inactive renin in nephrectomized rat plasma is not prorenin. In the present study, the trypsin-induced angiotensin I generating activity not related to prorenin from normal rat plasma disappeared after HPLC on G3000SW. HPLC analysis of trypsin-treated plasma showed the generation of active renin by trypsin for normal rat plasma, while it did not for nephrectomized rat plasma. These results indicate that trypsin treatment of crude plasma results in the generation of angiotensin I generating activity not due to prorenin, as well as activation of prorenin. HPLC on G3000SW is a useful tool for the determination of plasma prorenin.Key words: prorenin, antibody against prorenin prosegment, trypsin treatment, molecular weight, nephrectomy.

Immunological evidence that kidney is primary source of circulating inactive prorenin in rats

1991 ◽  
Vol 260 (4) ◽  
pp. E526-E536 ◽  
Author(s):  
S. Kim ◽  
M. Hosoi ◽  
K. Nakajima ◽  
K. Yamamoto
Keyword(s):  
High Performance ◽  
Primary Source ◽  
Rat Plasma ◽  
Immunoaffinity Chromatography ◽  
Bilateral Nephrectomy ◽  
Trypsin Treatment ◽  
Active Renin ◽  
Normal Rat ◽  
Inactive Renin ◽  
Immunoaffinity Columns

To determine whether or not rat plasma inactive renin is prorenin, specific antibodies were raised against two 15-amino acid peptides, Pro-NH2 and Pro-COOH, which contained the NH2-terminal and COOH-terminal sequences, respectively, of the prosegment of rat prorenin. Inactive renin was measured after trypsin treatment. Immunoaffinity chromatography of normal rat plasma on anti-Pro-NH2 and anti-Pro-COOH immunoglobulin G (IgG)-Sepharose showed that about one-half the amount of inactive renin was prorenin, whereas the rest was neither prorenin nor renin. Thus trypsin treatment of the unfractionated plasma does not provide measurement of the concentration of prorenin. However, fractionation of plasma by high-performance liquid chromatography on G3,000SW columns followed by trypsin treatment led to the measurement of prorenin. Prorenin and active renin concentrations in the normal plasma of conscious rats were 44.3 +/- 5.8 and 13.3 +/- 1.4 (SE) ng ANG I.h-1.ml-1, respectively (n = 10). On the other hand, plasma inactive renin from rats at 24 h after bilateral nephrectomy bound to neither anti-Pro-NH2 nor anti-Pro-COOH IgG immunoaffinity columns, and the enzymatic activity after trypsin treatment was not inhibited by anti-mature renin IgG. These results demonstrate that inactive renin from nephrectomized rats was not prorenin. Thus the kidney is the primary source of circulating prorenin in rats.

Trypsin activation of inactive renin: plasma blanks and angiotensin I radioimmunoassay

1991 ◽  
Vol 69 (9) ◽  
pp. 1315-1320 ◽  
Author(s):  
Jack D. Barrett ◽  
Peter Eggena
Keyword(s):  
Substrate Concentration ◽  
Rat Plasma ◽  
Direct Proportion ◽  
Trypsin Treatment ◽  
Angiotensin I ◽  
Renin Substrate ◽  
Active Renin ◽  
Normal Plasma ◽  
Inactive Renin ◽  
Significant Bearing

Divergent conclusions exist as to whether inactive renin is present in nephrectomized rat plasma. A major factor contributing to this conflict may be related to significant changes in the "plasma blank" when trypsin-treated plasma is subjected to angiotensin I (AI) radioimmunoassay (RIA). In normal, but not nephrectomized rat plasma, AI-like substances are present in direct proportion to active renin. These substances are destroyed by trypsin. However, trypsin generates additional AI-like material, in both normal and nephrectomized rat plasma. This material, which is present in proportion to the renin substrate concentration, does not appear to be tetradecapeptide (TDP). In normal plasma, however, exogenous TDP is converted to AI in proportion to the active renin concentration and AI generation from TDP is increased by activation of inactive renin. However, in nephrectomized rat plasma, no AI generation from TDP was evident either before or after trypsin treatment. The coincident tryptic generation of a substance that quenches the levels of AI detected by RIA, combined with significant changes in the levels of endogenous and trypsin generated AI-like substances, may have significant bearing on the measured levels of inactive renin.Key words: prorenin, nephrectomy, angiotensin I radioimmunoassay, rat, plasma blanks.

Activation and measurement of plasma prorenin in the rat

1991 ◽  
Vol 69 (9) ◽  
pp. 1331-1340 ◽  
Author(s):  
P. Ioannou ◽  
A. Y. Loh ◽  
D. H. Osmond
Keyword(s):  
Human Plasma ◽  
Rat Plasma ◽  
Blood Collection ◽  
Angiotensin I ◽  
Renin Substrate ◽  
Blood Samples ◽  
Functional Component ◽  
Fresh Frozen ◽  
Normal Rat

Prorenin determination in rat plasma has been problematic from the outset. Consequently, its existence is questioned by some and its quantity by others, making it difficult for knowledge to advance as to its function relative to the renin system. The present study examines major variables in the determination of rat plasma prorenin and renin, notably different prorenin activation protocols involving blood samples obtained under various conditions from animals under different anesthetics. We found that a trypsin activation step with 5 mg/mL plasma, 60 min at 23 °C, followed by a PRA step of 10 min at 37 °C, resulted in the highest prorenin estimates, up to approximately 400 ng∙mL−1∙h−1 in terms of angiotensin I, as compared with published values of 0–190, based on other protocols. These estimates were obtained despite considerable destruction of angiotensinogen (renin substrate) by trypsin. Cryoactivation of prorenin was much less effective than in human plasma but, when followed by trypsin, it facilitated greater activation than with trypsin alone. Comparable fresh and fresh-frozen plasmas had similar prorenin–renin values, but lower values were observed in plasmas that had been repeatedly frozen and thawed. Conscious rats and those anesthetized with Inactin or ether had higher renins and prorenins than those anesthetized with methoxyflurane or halothane. Rats with kidneys in place during blood collection had higher renins (but not prorenins) than those whose kidneys were clamped off, suggesting that last-minute renin release during blood collection had occurred. We conclude that (i) trypsin generates increased renin, or renin-like, activity in plasma, suggesting activation of a precursor; (ii) on this basis, high prorenin levels exist in normal rat plasma; (iii) renin and prorenin levels are variously influenced by different anesthetics and blood handling procedures; (iv) variation in prorenin levels suggests that it is a dynamic (functional?) component of the renin system; (v) prorenin measurements are heavily influenced by methodological variations during the trypsin step or the subsequent PRA step; (vi) using standardized methodology, the rat can serve as a model for investigating the function of prorenin in normotension and hypertension.Key words: tryptic activation, angiotensinogen, adrenalectomy, anesthesia.

Measurement of inactive renin in normal, nephrectomized, and adrenalectomized rats

1991 ◽  
Vol 69 (9) ◽  
pp. 1381-1384 ◽  
Author(s):  
Knud Poulsen ◽  
Arne Høj Nielsen ◽  
Arne Johannessen
Keyword(s):  
Animal Model ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Plasma Renin ◽  
Rat Plasma ◽  
Angiotensin I ◽  
Renin Substrate ◽  
Suitable Animal Model ◽  
Inactive Renin ◽  
Adrenalectomized Rats

In a new method for measurement of inactive rat plasma renin, the trypsin generated angiotensin I immunoreactive material, which was HPLC characterized as similar to tetradecapeptide renin substrate, is removed by a cation exchange resin before the renin incubation step. The method also corrects for trypsin destruction of endogenous angiotensinogen by the addition of exogenous angiotensinogen. When measured with this method inactive renin in rat plasma decreased after nephrectomy and increased after adrenalectomy. This is in accordance with findings in humans. A sexual dimorphism of prorenin (inactive renin) in rat plasma, similar to that reported in humans and mice, was demonstrated. Thus, inactive renin in the rat is no exception among species, and the rat might be a suitable animal model for further studies dealing with the physiology of prorenin in plasma and tissues.Key words: angiotensinogen, inactive renin, renin.

Effect of Acid, Trypsin and Cold Treatment and of Renin— Plasma Interaction on the Activity of Renin Secreted by Rat Kidney

1979 ◽  
Vol 57 (3) ◽  
pp. 233-240 ◽  
Author(s):  
H. Nakane ◽  
Y. Nakane ◽  
P. Corvol ◽  
J. Menard
Keyword(s):  
Rat Kidney ◽  
Cold Treatment ◽  
Rat Plasma ◽  
Renin Activity ◽  
Trypsin Treatment ◽  
Plasma Interaction ◽  
Isolated Perfused Rat Kidney ◽  
Perfused Rat Kidney ◽  
Inactive Renin ◽  
The Difference

1. Renin release from the isolated perfused rat kidney was markedly stimulated by isoprenaline or anoxia. Renin secreted into the blood-free perfusate was not activated by exposure to cold or dialysis to pH 3·3, suggesting the absence either of cryo- or acid-activatable renin or of factors necessary to activate inactive renin. 2. Trypsin treatment did not change renin concentration in the perfusate samples. 3. When binephrectomized rat plasma was added to perfusate samples before dialysis, renin concentration in the acidified samples was significantly higher than in samples dialysed to pH 6·5. Diminished renin recovery in the latter samples caused this difference. Binephrectomized rat plasma itself had no significant renin activity before or after acid dialysis, indicating the absence of any important extrarenal source of active or acid-activatable renin in rats. 4. Acidification of binephrectomized rat plasma before its addition to the perfusate samples markedly reduced the difference between renin recovery during dialysis to pH 3·3 and dialysis to pH 6·5, indicating that acidification irreversibly inhibited renin inactivation by binephrectomized rat plasma. No net increase in renin concentration was observed in any of our experiments. 5. These results suggest that rat kidney does not secrete inactive renin. They also point to the existence of renin inactivation by rat plasma at neutral pH, which might lead to overestimation of acid-activatable renin in rats.

EFFECT OF INHIBITION OF CONVERTING ENZYME ON INACTIVE RENIN IN THE CIRCULATION OF SALT-REPLETE AND SALT-DEPLETE NORMAL SUBJECTS

1980 ◽  
Vol 86 (2) ◽  
pp. 329-335 ◽  
Author(s):  
J. A. MILLAR ◽  
M. T. HAMMAT ◽  
C. I. JOHNSTON
Keyword(s):  
Angiotensin Ii ◽  
Normal Subjects ◽  
Inhibitory Influence ◽  
Converting Enzyme ◽  
Angiotensin I ◽  
Active Inhibitor ◽  
Active Renin ◽  
Angiotensin I Converting Enzyme ◽  
Inactive Renin ◽  
Orally Active

Angiotensin II exerts an inhibitory influence on active renin release from the kidney. To assess a possible role for angiotensin II in the release of inactive renin, levels in the circulation were measured before and at regular intervals after the administration of captopril, an orally active inhibitor of angiotensin I-converting enzyme, to 12 salt-replete and six salt-deplete normal subjects. Concurrent measurements of active renin, angiotensin I and angiotensin II were also performed. Basal inactive renin in the salt-deplete group was increased compared with the salt-replete subjects, but inactive renin remained constant in both groups after treatment with captopril. There were significant increases in concentrations of both active renin and angiotensin I after treatment with captopril in all subjects and corresponding decreases in angiotensin II. These results suggested that angiotensin II does not influence the release of inactive renin, in contrast with its role in the release of active renin.

Prorenin is present in human red blood cells

1991 ◽  
Vol 69 (9) ◽  
pp. 1394-1397 ◽  
Author(s):  
C. Troffa ◽  
G. Tonolo ◽  
P. Manunta ◽  
A. Pazzola ◽  
A. Soro ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Blood Cells ◽  
Normal Subjects ◽  
Trypsin Treatment ◽  
Angiotensin I ◽  
Hypertensive Patients ◽  
Human Red Blood Cells ◽  
Before And After ◽  
Inactive Renin ◽  
Homologous Substrate

We looked for the presence of prorenin in erythrocytes from normal subjects (n = 8), hypertensive patients (n = 8), and pregnant women (n = 8). Angiotensin I generation was measured at 37 °C, pH 5.7, in the presence of homologous substrate (1400 ng/mL) before and after trypsin activation (100 μg/mL) in (A) haemolyzed erythrocytes, (B) supernatants of haemolyzed erythrocytes, and (C) in the sixth washing of erythrocytes diluted 1:1 with a 0.1 M Tris buffer containing 0.5% bovine serum albumin and protease inhibitors. Haemolyzed erythrocytes generated angiotensin I only after trypsin treatment, and the rate of generation was the same (A) before and (B) after centrifugation at 20000g, indicating the absence of prorenin bound to the cell membranes. When aliquots of the last washing of erythrocytes (C) were tested for angiotensin I generation before and after trypsin, they did not generate angiotensin I, indicating that residual prorenin from the plasma was no longer present in our preparation. Angiotensin I generation by trypsin-treated A and B was completely abolished by preincubation with anti-renin serum. The level of prorenin was not significantly different in the erythrocytes from normal, hypertensive, and pregnant subjects (68 ± 10, 58 ± 7 and 107 ± 17 pg angiotensin I∙mL−1∙h−1, ns) in spite of their very different plasma levels (21 ± 2.5, 17 ± 2.4 and 110 ± 12 ng angiotensin I∙mL−1∙h−1, p < 0.01 for pregnant women compared with both normal and hypertensive subjects). Our data show that prorenin is present in human erythrocytes in fairly constant and clearly detectable amounts, thus suggesting a possible intracellular role for it.Key words: inactive renin, intracellular prorenin, erythrocytes, prorenin.

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)

scholarly journals Studies on the Uncrosslinked Fraction of PLA/PBAT Blends Modified by Electron Radiation

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1068 ◽  
Author(s):  
Rafał Malinowski ◽  
Krzysztof Moraczewski ◽  
Aneta Raszkowska-Kaczor
Keyword(s):  
Molecular Weight ◽  
Fourier Transform ◽  
Thermal Properties ◽  
Infrared Spectroscopy ◽  
Quantitative Analysis ◽  
Average Molecular Weight ◽  
The Other ◽  
Electron Radiation ◽  
Different Molecular Weight

The results of studies on the uncrosslinked fraction of blends of polylactide and poly(butylene adipate-co-terephthalate) (PLA/PBAT) are presented. The blends were crosslinked by using the electron radiation and triallyl isocyanurate (TAIC) at a concentration of 3 wt %. Two kinds of samples to be investigated were prepared: one contained 80 wt % PLA and the other contained 80 wt % PBAT. Both blends were irradiated with the doses of 10, 40, or 90 kGy. The uncrosslinked fraction was separated from the crosslinked one. When dried, they were subjected to quantitative analysis, Fourier transform infrared spectroscopy (FTIR) measurements, an analysis of variations in the average molecular weight, and the determination of thermal properties. It was found that the electron radiation caused various effects in the studied samples, which depended on the magnitude of the radiation dose and the weight fractions of the components of the particular blends. This was evidenced by the occurrence of the uncrosslinked fractions of different amounts, a different molecular weight distribution, and the different thermal properties of the samples. It was also concluded that the observed effects were caused by the fact that the processes of crosslinking and degradation took place mostly in PLA, while PBAT appeared to be less susceptible to the influence of the electron radiation.

scholarly journals A study of the electrochemical behavior of methomyl on a gold electrode in a neutral electrolyte

2009 ◽  
Vol 74 (5) ◽  
pp. 573-579 ◽  
Author(s):  
Andjelka Tomasevic ◽  
Milka Avramov-Ivic ◽  
Slobodan Petrovic ◽  
Mica Jovanovic ◽  
Dusan Mijin
Keyword(s):  
Gold Electrode ◽  
Hplc Analysis ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Determination ◽  
The Other ◽  
Potential Range ◽  
Linear Sweep ◽  
Qualitative And Quantitative ◽  
Neutral Electrolyte

A gold electrode was used for the qualitative and quantitative electrochemical determination of analytical methomyl in a neutral electrolyte (0.050 M NaHCO3) using cyclic linear sweep voltammetry. In the potential range from -800 mV vs. SCE to 1000 mV vs. SCE the analytical methomyl was quantitatively determined in the concentration range 4.0-16 mg L-1. In the potential range from -1300 mV vs. SCE to 1300 mV vs. SCE, methomyl was qualitatively determined by two anodic and four cathodic reactions. Cycling the potential in this range for 150 min caused the degradation of the molecule, which was confirmed by HPLC analysis. On the other hand, technical methomyl exhibited an inhibition of the gold electrode surface due to the impurities.

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