Assay of Tissue Angiotensin Converting Enzyme

Welsch, C; Grima, Michèle; Giesen, E. M.; Helwig, J. J.; Barthelmebs, Mariette; Coquard, Catherine; Jl, Imbs

doi:10.1097/00005344-198900000-00007

Cited by 21 publications

(11 citation statements)

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“…Because tissue ACE is a membrane-bound enzyme, all the tissues were treated with Triton X-100 for total extraction and solubilization of ACE, which allowed us to obtain high binding. 6 This in vitro determination of ACE inhibition on tissue extracts ruled out the influence of the bioavailability and the physicochemical properties of the ACE inhibitors. No difference was detected between hypertensive and normotensive rats.…”

Section: Discussionmentioning

confidence: 94%

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In vitro tissue potencies of converting enzyme inhibitors. Prodrug activation by kidney esterase.

et al. 1991

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The inhibition of angiotensin converting enzyme by ramipril, ramiprilat, enalapril, enalaprilat, and captopril was studied in the plasma and various tissues (lung, heart, renal cortex, renal medulla) of normotensive rats and spontaneously hypertensive rats. Displacement curves for [ 3 H] ramiprilat were established on each tissue with the converting enzyme inhibitors, and their potencies were expressed as the concentration that inhibited 50% of the specific [ 3 H] ramiprilat binding. In the plasma, lung, and heart, the order of activities was: ramiprilat >enalaprilat> captopril > ramipril > enalapril. This order was different in the kidney (cortex and medulla): ramiprilat>enalaprilat>ramipril>captopril>enalapril. For ramiprilat, enalaprilat, and captopril, there were no differences in their respective potencies between tissues or between rat strains. However, the two prodrugs ramipril and enalapril were 10-30 times more active in the kidney than in the other tissues in both groups of rats. This was due to the deesterification of the prodrugs: in the presence of an esterase inhibitor (diethyl nitrophenyl phosphate, 10 /AM), the potencies of ramipril in the kidney were not different from that obtained in the lung, which was not affected by the presence of the esterase inhibitor. These results suggest that the variations in the tissue activities of an angiotensin converting enzyme inhibitor are probably not due to differences in tissue affinities of the angiotensin converting enzyme inhibitor but depend on the concentration of this angiotensin converting enzyme inhibitor in each tissue. (Hypertension 1991;17:492-496)

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Section: Discussionmentioning

confidence: 94%

“…Radioactivity was measured in a Packard counter with a 58% efficiency. Binding experiments were performed at a protein concentration that ensured linearity between binding and protein concentration 6 and binding of less than 10% of added …”

Section: Plasma and Tissue Samplingmentioning

confidence: 99%

In vitro tissue potencies of converting enzyme inhibitors. Prodrug activation by kidney esterase.

et al. 1991

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“…To ensure a linear relation between ACE activity and protein content, the protein concentration in the assay was maintained at less than 2 mg/mL (tissue) or 20 mg/mL (plasma). 6 The protein concentration was determined by the method of Lowry et al 7 using bovine serum albumin fraction V (Sigma Chemical Co., St. Louis, Mo.) as standard.…”

Section: Determination Of Angiotensin Converting Enzyme Activitymentioning

confidence: 99%

Angiotensin converting enzyme variability in hypertensive and normotensive rats.

et al. 1993

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Recent data have revealed biological and genetic variability in normotensive Wistar-Kyoto rats, which are considered to be the most appropriate control strain for spontaneously hypertensive rats. To investigate the possibility that angiotensin converting enzyme activity could be affected by this variability, we measured plasma and tissue (lung, heart, renal cortex, renal medulla, and adrenal gland) angiotensin converting enzyme activity in spontaneously hypertensive rats and normotensive Wistar-Kyoto rats from three commercial suppliers in France: Iffa-Credo, Janvier, and Charles River Laboratories. Angiotensin converting enzyme activity was measured in vitro with a fluorometric assay using carbobenzoxy-Phe-HisLeu as substrate. Angiotensin converting enzyme activity in both rat strains varied considerably from one supplier to another, and therefore, comparisons of spontaneously hypertensive rats and Wistar-Kyoto rats from the different suppliers produced conflicting results. For Wistar-Kyoto rats, angiotensin converting enzyme activity in the plasma, heart, kidney, and adrenal glands was highest in rats from Iffa-Credo and lowest in rats from Charles River. For spontaneously hypertensive rats, angiotensin converting enzyme activity in the plasma and tissues was highest in rats from Janvier, whereas no difference could be observed between rats from Iffa-Credo and Charles River. These data confirm the problem of how to interpret and compare studies that use spontaneously hypertensive and Wistar-Kyoto rat strains. (Hypertension 1993^1:442-445) KEY WORDS • kininase II • rats, inbred WKY • rats, inbred SHR S pontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats are widely compared with respect to their cardiovascular phenotypes as models for the study of hypertension. Although both strains have been assumed to be fully inbred, recent data have revealed that biological and genetic variations exist among WKY rats bred in different laboratories, as well as among SHR.1 -4 To investigate the possibility that angiotensin converting enzyme (ACE) activity could be affected by this variability, we obtained SHR and WKY rats from three commercial suppliers in France and measured plasma and tissue (lung, heart, renal cortex, renal medulla, and adrenal gland) ACE activities in these rats under standardized environmental and experimental conditions. Methods AnimalsEight-week-old male SHR and WKY rats were purchased simultaneously from three different suppliers in

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“…Plasma tissue ACE activity has been studied using in vivo single pass kinetic studies in animals (Catravas & White, 1984;Chen et al, 1984;Linehan et al, 1990;Moalli et al, 1985 (Cohen & Kurz, 1982;Sakaguchi et al, 1988a,b,c;Welsch et al, 1989 We have conducted a small series of transpulmonary observations using the intravenous diacid ACE inhibitor perindoprilat co-infused with the intravascular marker dye indocyanine green. These studies were conducted in an attempt to use the plasma drug concentration time profile of the ACE inhibitor to define pulmonary ACE binding during low dose constant rate intravenous infusion in man.…”

Section: Pulmonary Ras and Ace Activitymentioning

confidence: 99%

Tissue and plasma angiotensin converting enzyme and the response to ACE inhibitor drugs.

Lees

Reid

1991

Brit J Clinical Pharma

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1. There is a body of circumstantial and direct evidence supporting the existence and functional importance of a tissue based RAS at a variety of sites. 2. The relation between circulatory and tissue based systems is complex. The relative importance of the two in determining haemodynamic effects is unknown. 3. Despite the wide range of ACE inhibitors already available, it remains unclear whether there are genuine differences related to tissue specificity. 4. Pathological states such as chronic cardiac failure need to be explored with regard to the contribution of tissue based ACE activities in generating acute and chronic haemodynamic responses to ACE inhibitors. 5. The role of tissue vs plasma ACE activity may be clarified by study of the relation between drug concentration and haemodynamic effect, provided that the temporal dissociation is examined and linked to circulating and tissue based changes in ACE activity, angiotensin peptides and sympathetic hormones.

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Assay of Tissue Angiotensin Converting Enzyme

Cited by 21 publications

References 0 publications

In vitro tissue potencies of converting enzyme inhibitors. Prodrug activation by kidney esterase.

In vitro tissue potencies of converting enzyme inhibitors. Prodrug activation by kidney esterase.

Angiotensin converting enzyme variability in hypertensive and normotensive rats.

Tissue and plasma angiotensin converting enzyme and the response to ACE inhibitor drugs.

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