Partial Characterization of Aortic Renin in the Spontaneously Hypertensive Rat and its Interrelationship with Plasma Renin, Blood Pressure and Sodium Balance

Barrett, J.; Eggena, Peter; Sambhi, Mohinder P.

doi:10.1042/cs0550261

Cited by 15 publications

(7 citation statements)

References 18 publications

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“…Renin activity within vascular tissue extracts has been demonstrated previously (Gould et al, 1964;Swales and Thurston, 1973;Basso and Taguini, 1974;Thurston and Swales, 1977;Barrett et al, 1978;Thurston et al, 1979;Aguilera et al, 1981). Arterial renin activity has been measured in the rat and shown to have a longer half-life after nephrectomy compared with plasma renin (Rosenthal et al, 1969;Thurston et al, 1977).…”

Section: Discussionmentioning

confidence: 98%

“…Angiotensin-converting enzyme (ACE), for example, has been localized to the endothelial cell surface (Ryan et al, 1976;Johnson et al, 1977;Hial et al, 1979), where it acts to convert angiotensin I (Al) to angiotensin II (All), thus serving to increase vascular smooth muscle tone. Although circulating renin has been considered to be the major ratelimiting determinant of All production, recent data suggest that renin residing within the vascular wall, or at the blood/vessel interface, may also play an important role (Gould et al, 1964;Swales and Thurston, 1973;Basso and Taguini, 1974;Thurston and Swales, 1977;Barrett et al, 1978;Thurston et al, 1979;Aguilera et al, 1981). However, the exact cellular localization of renin in blood vessels in vivo and its site(s) of synthesis remain incompletely understood.…”

Section: Renin Expression By Vascular Endothelial Cells In Culturementioning

confidence: 99%

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Renin expression by vascular endothelial cells in culture.

Lilly¹,

Pratt²,

Alexander³

et al. 1985

Circulation Research

111

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SUMMARY. Cultured bovine aortic endothelial cells were examined for renin activity by biochemical, immunological, and immunohistochemical techniques. When cell sonicates were incubated with renin substrate, linear generation of angiotensin I was observed (1.12 ± 0.2 ng angiotensin I/10 6 cells per hr). The effect of pH on this activity was similar to that of bovine renal renin, and renin antibodies inhibited a large portion of the enzymatic activity. Furthermore, immunofluorescence microscopy with antirenin antisera confirmed the presence of renin within these cells. Biosynthetic radiolabeling, followed by immunoprecipitation, demonstrated de novo synthesis of a renin precursor in the endothelial cells, which was processed to a more mature protein. Thus, bovine aortic endothelial cells in culture contain and biosynthesize renin, a key component of the renin-angiotensin system. The expression of renin activity by endothelium may contribute to the local regulation of vascular tone. (Ore Res 57: 312-318, 1985)

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Section: Discussionmentioning

confidence: 98%

Section: Renin Expression By Vascular Endothelial Cells In Culturementioning

confidence: 99%

Renin expression by vascular endothelial cells in culture.

Lilly¹,

Pratt²,

Alexander³

et al. 1985

Circulation Research

111

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“…The presence in arterial tissue of an enzyme that releases a pressor substance from plasma has long been known." Kinetic studies of aortic renin by Gould et al 7 in the dog and more recently by Barrett et al 10 in the rat indicate that the enzyme present generates angiotensin and has a similar pH optimum and K m to renal renin. The present work confirms the presence of such an enzyme in aortic wall preparation.…”

Section: Discussionmentioning

confidence: 99%

Vascular renin-like activity and blood pressure maintenance in the rat. Studies of the effect of changes in sodium balance, hypertension and nephrectomy.

Thurston¹,

Swales²,

Bing³

et al. 1979

Hypertension

102

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SUMMARY Aortic renin-like activity and plasma renin concentration were measured in rats subjected to dietary salt loading or depletion. Homogenates prepared from rat aortic tissue generated angtotensin I from plasma substrate at both pH S3 and pH 6.5. Aortic renin-like activity measured at incubation pH 6.5 and plasma renin concentration changed in parallel, rising with salt restriction and falling with salt loading. However, the capacity of aortic bomogenate to generate angiotensin I at an incubation pH of 53 did not snow any signiflcant change with alteration of sodium balance. In addition, administration of the converting enzyme inhibitor (CEI) SQ20,881 produced a greater fall of blood pressure in salt-depleted than salt-loaded animals.In order to determine whether arterial or plasma renin was the important variable in blood pressure regulation, the depressor response to CEI was studied in GoMMatt two-kidney, one dip hypertensive rats before and 1, 2, 6 and 24 hours after bilateral nephrectomy. Aortic and plasma renin concentration were measured in a second series of hypertensive rats at the same times after bilateral nephrectomy. Although plasma renin concentration showed tbe expected fall to basal levels within 1 hour, a signiflcant depressor response to CEI was observed at 1 and 2 hours after bilateral nephrectomy, with a smaller fall at 6 hours. When a competitive antagonist of angiotensin II (saralasin) was infused, a significant fall in Mood pressure occurred 1 hour after bilateral nephrectomy, and no further fall was induced by injection of CEI. Thus, the fall of blood pressure induced by CEI was due to renin-angiotensin blockade and not an additional hypotensive effect Aortic renin-like activity measured at an incubation pH of 6.5 fell slowly after bilateral nephrectomy and was significantly lower only at 6 and 24 hours. This closely parallels the reduction of depressor response observed with converting enzyme inhibitor. However aortic renln-Uke activity measured at pH 5 J showed no significant change at anytime after bilateral nephrectomy except for activity after 1 hour, which was significantly elevated. This evidence supports more indirect studies which have suggested that arterial renin-like activity derived from the kidney is important in blood pressure maintenance by tbe local generation of angiotensin II, and that this activity has a longer half-life than plasma renin. Enzymic activity detected at a low incubation pH probably represents a tissue enzyme that is not important in blood pressure maintenance. . 4 ' 6 The components of the renin-angioelevated plasma renin levels are associated with a tensin system are present in the circulation, where depressor response to pharmacological antagonism of generation of the effector hormone of the system, the renin-angiotensin system. 15 The extent of this role angiotensin II takes place. However, renin-like enis controversial as there are differences in the zymes are also present in many other tissues 6 and angiotensin II could therefore be generated lo...

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“…21 - 22 It was not our intention to further investigate the issue of elevated arterial AIFE in SHR, but to examine whether aortic AIFE of SHR is identical with that of normotensive controls. The isoelectric points of aortic AIFE from both groups of animals were found to be identical, that is, 5.6.…”

Section: Angiotensin Levelsmentioning

confidence: 99%

Investigations of components of the renin-angiotensin system in rat vascular tissue.

Rosenthal¹,

Pfeifle²,

Michailov³

et al. 1984

Hypertension

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SUMMARY Investigations were performed on components of the renin-angiotensin system (RAS) in homogenate extracts of vascular tissue and aortic smooth muscle cells cultivated in vitro. Determinations of isoelectric points and pH optima indicated the existence in aortic homogenate extracts of two local angiotensin I (AI)-forming enzymes (AIFE) that were different from those of plasma, renal cortex, veins, and aortic smooth muscle cells. The pH optima for Al-converting enzyme (ACE) from vascular tissues, aortic smooth muscle cells, and plasma were in the same range (pH 8.0-8.5), and in agreement with those measured previously in other tissues. In contrast, in vitro studies with the ACE inhibitors MK-421 and MK-422 and measurement of isoelectric points suggested that aortic ACE was different from the plasma enzyme. AIFE and ACE activities were found to be elevated in spontaneously hypertensive rats (SHR). The biochemical characteristics of the enzymes investigated in the vascular tissue of SHR were not different from those of the normotensive controls. AI-and All-degrading enzymes were found both in aortic tissue and in aortic smooth muscle cells. One potent Al-degrading enzyme different from ACE was observed in aortic tissue. A high ratio of AI/AII immunoreactivities in arterial walls suggests the availability of renin substrate, and that Al-degrading enzymes are the rate-limiting enzymes for AH formation. were the first to demonstrate the existence of arterial and also venous wall renin by using systematically performed biochemical methods. In the last few years, there has been renewed interest in the vascular reninangiotensin system (RAS). Now, as before, it is thought to play a role in the regulation of blood pressure and in the development and maintenance of hypertension. The present investigation continues our previous studies in this field 4 ' 3 and was undertaken to recognize, quantify, and partly characterize those components of

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Partial Characterization of Aortic Renin in the Spontaneously Hypertensive Rat and its Interrelationship with Plasma Renin, Blood Pressure and Sodium Balance

Cited by 15 publications

References 18 publications

Renin expression by vascular endothelial cells in culture.

Renin expression by vascular endothelial cells in culture.

Vascular renin-like activity and blood pressure maintenance in the rat. Studies of the effect of changes in sodium balance, hypertension and nephrectomy.

Investigations of components of the renin-angiotensin system in rat vascular tissue.

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