Trypsin-Activatable Inactive Renin in Rat Plasma

1983 ◽  
Vol 64 (2) ◽  
pp. 137-140 ◽  
Author(s):  
Nicola Glorioso ◽  
Paolo Madeddu ◽  
Paolo Dessi'-Fulgheri ◽  
Giuseppe Fois ◽  
Franca Meloni ◽  
...  
Keyword(s):  
Rat Plasma ◽  
Renin Activity ◽  
Trypsin Activity ◽  
Ph Optimum ◽  
Renin Substrate ◽  
Inactive Form ◽  
Wide Range ◽  
Maximal Activation ◽  
Inactive Renin ◽  
Range Of Variation

1. Activation of inactive renin in rat plasma has been studied with different trypsin concentrations and incubation times at pH 6.2 and 4°C. 2. Trypsin concentrations below 2 mg/ml, lower than endogenous rat plasma anti-trypsin activity, do not activate inactive renin, whereas maximal activation is obtained with trypsin at 6 mg/ml for 1 min at 4°C, pH 6.2. 3. Under these conditions trypsin can cleave dialysable fragments from renin substrate. ANG I can be generated at 37°C with a pH optimum of 5.3. Nevertheless, the ANG I formation at pH 6.2 was totally unaffected. 4. Incubations longer than 2 min with trypsin at 6 mg/ml can induce a direct cleavage of dialysable ANG I-containing fragments strongly interfering with the measurements of renin activity at pH 6.2. 5. On average 40% of the total renin measured in plasma of normotensive WK rats is in the inactive form, although a wide range of variation is observed.

Effects of stimulation of renin release on trypsin-activable renin in rat plasma

1982 ◽  
Vol 243 (3) ◽  
pp. E206-E212 ◽  
Author(s):  
J. D. Barrett ◽  
P. Eggena ◽  
J. R. Sowers ◽  
M. P. Sambhi
Keyword(s):  
Plasma Renin ◽  
Rat Plasma ◽  
Assay Method ◽  
Ph Optimum ◽  
Inactive Form ◽  
Normal Rat ◽  
Inactive Renin ◽  
Arteries And Veins ◽  
Stimulation Of

Little information is available concerning inactive renin in rat plasma. A renin assay method has now been developed for measurement of active and inactive renin in approximately 0.1 ml rat plasma. Trypsin treatment of plasma (5.0 mg trypsin/ml plasma for 5 min at 0 degrees C) to maximally increase the rate of angiotensin I generation did not alter the Km or pH optimum of the renin reaction. Utilizing trypsin, 79 +/- 6% of the total renin (active + inactive) in normal rat plasma is in the inactive form. In vivo stimulation of renin by restraint stress induces a reciprocal change in active and inactive plasma plasma renin, and exposure of animals to ether elevates active and total renin, whereas inactive renin shows a small but nonstatistical decline. Although a parallel disappearance of active and inactive renin is observed after bilateral nephrectomy of the pentobarbital-anesthetized animal, complete occlusion of the renal arteries and veins after ether-induced renin stimulation results in a significant increase of inactive renin. This suggests that possibility of formation of inactive renin from the active enzyme in high renin states. These studies indicate that the balance of active and trypsin-activable renins in rat plasma may be dependent or not only the method but also the degree of in vivo renin stimulation.

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.

Does heparin inhibit renin activity?

1991 ◽  
Vol 69 (9) ◽  
pp. 1360-1363 ◽  
Author(s):  
Masato Matsunaga ◽  
Yoko Yamanaka ◽  
Noriko Nagano ◽  
Yuki Iwasaki ◽  
Yumi Saito ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Vascular Smooth Muscle Cell ◽  
Plasma Renin ◽  
Renin Activity ◽  
Renin Substrate ◽  
Significant Difference ◽  
Inactive Renin

Although heparin was reported in the 1960s to inhibit renin activity, this has not always been confirmed by other investigators. Hence, we re-examined whether heparin really inhibits renin or not. Renin activities were determined by radioimmunoassay of angiotensin I generated at pH 7.4. (i) No significant difference was found between the two kinds of plasma samples obtained with heparin and with EDTA as anticoagulant, in ARC (renin activity with addition of sheep renin substrate), TRC (ARC after activation of inactive renin by trypsin), or PRA (plasma renin activity without additional substrate), (ii) Even in higher concentrations of heparin up to 500 U/mL, neither PRA, ARC, nor TRC of plasma was affected significantly. (iii) Heparin, in concentrations up to 500 U/mL, exerted no significant effect on TRC of the media of human vascular smooth muscle cell culture. In conclusion, heparin does not exert any significant inhibitory effect on human renin nor does it affect activation of inactive renin by trypsin in the range of concentration of practical use, under the conditions employed in this study.Key words: plasma renin, tissue renin, inactive renin, vascular smooth muscle cell, trypsin.

Absence of Activation in Vitro of Renin in Rat Plasma

1982 ◽  
Vol 62 (4) ◽  
pp. 435-437 ◽  
Author(s):  
M. H. De Keijzer ◽  
A. P. Provoost ◽  
F. H. M. Derkx
Keyword(s):  
Human Plasma ◽  
Active Form ◽  
Plasma Renin ◽  
Rat Plasma ◽  
Plasma Renin Concentration ◽  
Inactive Form ◽  
Inactive Renin

1. Rat plasma was subjected at 4°C to various treatments known to convert inactive renin into its active form in human plasma. 2. No statistical differences in plasma renin concentration were found when the levels after the various treatments were compared with that of untreated rat plasma. 3. It is concluded that, in contrast to human plasma, no inactive form of renin is present in rat plasma.

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.

Cryoactivation of Plasma Renin

1978 ◽  
Vol 55 (s4) ◽  
pp. 139s-141s ◽  
Author(s):  
A. Hara ◽  
M. Matsunaga ◽  
J. Yamamoto ◽  
K. Morimoto ◽  
H. Nagai ◽  
...  
Keyword(s):  
Low Temperature ◽  
Human Plasma ◽  
Trypsin Inhibitor ◽  
Plasma Renin ◽  
Haemorrhagic Shock ◽  
Rat Plasma ◽  
Renin Activity ◽  
Plasma Samples ◽  
Renin Substrate

1. The mechanism of increased renin activity after human plasma had been kept at −5°C for 4 days (cryoactivation) was investigated. 2. The increase in renin activity of human plasma by cryoactivation was closely correlated to the increase obtained by incubation with trypsin (r = 0·88, P < 0·001, n = 10). 3. An inhibitor of thiol enzyme, N-ethylmaleimide did not inhibit cryoactivation. 4. Soyabean trypsin inhibitor and di-isopropylfluorophosphate (DFP) inhibited cryoactivation, suggesting that the cryoactivation may be due to the action of a trypsin-like serine enzyme. 5. In an experiment in the rat haemorrhagic shock caused parallel increments of renin activity in non-cryoactivated and cryoactivated plasma, the renin activity being about two times higher in the latter. No significant differences were found in the concentrations of renin and renin substrate between the non-cryoactivated and cryoactivated plasma samples. 6. The results may indicate that a destruction of an inhibitor of the renin—renin substrate reaction is responsible for the increase of renin activity after exposure of rat plasma to low temperature. A trypsin-like enzyme in plasma might have destroyed the inhibitor during this procedure.

Enzymatic Activity of Renin in Plasma of Normal and Uraemic Subjects

1984 ◽  
Vol 67 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Theodore A. Kotchen ◽  
Tam T. Guyenne ◽  
Pierre Corvol ◽  
Joel Menard
Keyword(s):  
Renal Failure ◽  
Enzymatic Activity ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Renin Activity ◽  
Angiotensin I ◽  
Renin Substrate ◽  
Inactive Renin ◽  
Substrate Concentrations

1. Plasma renin reactivity (PRR) is the rate of angiotensin I production after addition of renin to plasma, minus endogenous renin activity. PRR is increased in plasma of patients with renal failure compared with that of normal subjects. The present study was carried out to determine if increased PRR in uraemic plasma is related to differences of endogenous active or inactive renin, endogenous renin substrate, or pH of the incubation in vitro. 2. PRR in plasma of ten uraemic patients was greater (P<0.02) than that in plasma of ten normal subjects in incubations carried out at pH 7.4 and 5.7. 3. Increased PRR was not accounted for by differences of endogenous active and inactive renin activity. 4. After addition of renin, renin concentration (measured by direct radioimmunoassay) did not differ in normal and uraemic plasma. 5. Renin substrate concentration, measured both indirectly and by direct radioimmunoassay, also did not differ in normal and uraemic plasma. 6. Increased PRR in uraemic plasma is not related to alterations of renin or renin substrate concentrations. These observations are consistent with our earlier hypothesis that there is a deficiency of a renin inhibitor in uraemic plasma.

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.

Angiotensins I and II, active and inactive renin, renin substrate, renin activity, and angiotensinase in human liquor amnii and plasma

1975 ◽  
Vol 121 (5) ◽  
pp. 626-630 ◽  
Author(s):  
S.L. Skinner ◽  
Elizabeth J. Cran ◽  
Robyn Gibson ◽  
R. Taylor ◽  
W.A.W. Walters ◽  
...  
Keyword(s):  
Renin Activity ◽  
Liquor Amnii ◽  
Renin Substrate ◽  
Inactive Renin

scholarly journals THE PRESENCE OF RENIN ACTIVITY IN BLOOD VESSEL WALLS

1964 ◽  
Vol 119 (3) ◽  
pp. 389-399 ◽  
Author(s):  
Anne B. Gould ◽  
Leonard T. Skeggs ◽  
Joseph R. Kahn
Keyword(s):  
Activation Energy ◽  
Blood Vessel ◽  
Blood Vessels ◽  
Substrate Concentration ◽  
Renin Activity ◽  
Ph Optimum ◽  
Energy Effect ◽  
Renin Substrate ◽  
Vessel Walls ◽  
Hydrolysis Of

The preparation, of an extract of hog blood vessels and organs containing renin activity has been described. The extract hydrolyzes natural or synthetic renin substrate to form a vasopressor material. This reaction could not be distinguished from the hydrolysis of renin substrates by kidney renin. The activation energy, effect of substrate concentration on velocity, inhibition by antirenin, and pH optimum of the extract and of kidney renin are the same. Renin activity is found in the adventitia and media of the aorta, the liver and, to a lesser extent, in other vascular organs.

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