Age-related variations in tissue angiotensin converting enzyme activities: comparison between spontaneously hypertensive and Wistar-Kyoto rats

Grima, Michèle; Welsch, C; Giesen-Crouse, Eva-Maria; Coquard, Catherine; Barthelmebs, Mariette; Imbs, Jean-Louis

doi:10.1097/00004872-199008000-00002

Cited by 16 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No difference was detected between hypertensive and normotensive rats. This agrees with other data for 3-week-old SHR and WKY rats, 13 showing that differences in ACE activities between the two strains resulted from differences in ACE concentration and not in enzyme affinity. The potency of ramiprilat was nearly identical in each of the five tissues studied, as were the relative potencies for enalaprilat and captopril.…”

Section: Discussionsupporting

confidence: 92%

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

et al. 1991

View full text Add to dashboard Cite

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)

show abstract

Section: Discussionsupporting

confidence: 92%

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

et al. 1991

View full text Add to dashboard Cite

show abstract

“…Lung and aorta required incubation times of 15 min. This is in accordance with previous reports showing a high ACE activity in lung and aorta (15,16).…”

Section: Discussionsupporting

confidence: 94%

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

Oliveira

Santos

Krieger

2000

Braz J Med Biol Res

View full text Add to dashboard Cite

The tripeptide Hip-His-Leu was used to standardize a fluorimetric method to measure tissue angiotensin-converting enzyme (ACE) activity in rats. The fluorescence of the o-phthaldialdehyde-His-Leu adduct was compared in the presence and absence of the homogenate (25 µl) to determine whether the homogenate from different tissues interfered with the fluorimetric determination of the His-Leu product. Only homogenates from lung and renal medulla and cortex showed significantly altered fluorescence intensity. To overcome this problem, the homogenate from these tissues were diluted 10 times with assay buffer. The specificity of the assay was demonstrated by the inhibition of ACE activity with 3 µM enalaprilat (MK-422). There was a linear relationship between product formation and incubation time for up to 90 min for homogenates of renal cortex and medulla and liver, for up to 60 min for ventricles and adrenals and for up to 30 min for the aorta, lung and atrium homogenates. In addition, there was a linear relationship between product formation and the amount of protein in the homogenates within the following range: lung, 30-600 µg; renal cortex and medulla, 40-400 µg; atrium and ventricles, 20-200 µg; adrenal, 20-100 µg; aorta, 5-100 µg; liver, 5-25 µg. No peptidase activity against the His-Leu product (31 nmol), assayed in borate buffer (BB), was detected in the different homogenates except the liver homogenate, which was inhibited by 0.1 mM r-chloromercuribenzoic acid. ACE activity in BB was higher than in phosphate buffer (PB) due, at least in part, to a greater hydrolysis of the His-Leu product in PB. ACE activity of lung increased 20% when BB plus Triton was used. Enzyme activity was stable when the homogenates were stored at -20 o or -70 o C for at least 30 days. These results indicate a condition whereby ACE activity can be easily and efficiently assayed in rat tissue samples homogenized in BB using a fluorimetric method with Hip-His-Leu as a substrate. Correspondence

show abstract

“…Thus, in a previous study, we were able to record age-related variations in ACE activity in SHR and WKY rats born and bred in our laboratory from parents purchased from IC. 10 The plasma and tissues of age-matched rats were comparable to those reported here. Little is known about hormonal control of ACE activity: plasma ACE levels are higher in hyperthyroidism in humans, 11 but, in healthy Caucasian men, no association was observed between ACE activity and plasma T3 level.…”

Section: Discussionsupporting

confidence: 77%

“…17 - 21 In previous work, we observed that the low level of ACE activity in SHR (IC) was present as early as the third week of life, before hypertension appeared, and that the development of high blood pressure did not modify ACE activity. 10 Nevertheless, it has recently been demonstrated that a gene (BP/SP.l, Bpl) located on chromosome 10 is associated with the development of hypertension.…”

Section: Figure 3 Bar Graphs Show Angiotensin Converting Enzyme (Acementioning

confidence: 99%

Angiotensin converting enzyme variability in hypertensive and normotensive rats.

et al. 1993

View full text Add to dashboard Cite

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

show abstract

Age-related variations in tissue angiotensin converting enzyme activities: comparison between spontaneously hypertensive and Wistar-Kyoto rats

Cited by 16 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.

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

Angiotensin converting enzyme variability in hypertensive and normotensive rats.

Contact Info

Product

Resources

About