Reduced lung endothelial angiotensin-converting enzyme activity in Watanabe hyperlipidemic rabbits in vivo

Stylianos E. Orfanos, James B. Parkerson, Xilin Chen, Lyle E Fisher, Constantinos Glynos, Andreas Papapetropoulos, Ross G. Gerrity, John D. Catravas

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We investigated pulmonary endothelial function in vivo in 12- to 18-mo- old male Watanabe heritable hyperlipidemic (WHHL; n = 7) and age- and sex- matched New Zealand White (n = 8) rabbits. The animals were anesthetized and artificially ventilated, and the chest was opened and put in total heart bypass. The single-pass transpulmonary utilizations of the angiotensin- converting enzyme (ACE) substrate [3H]benzoyl-Phe-Ala-Pro (BPAP) and the 5'- nucleotidase (NCT) substrate [14C]AMP were estimated, and the first-order reaction parameter A(max)/K(m), where A(max) is the product of enzyme mass and the catalytic rate constant and K(m) is the Michaelis-Menten constant, was calculated. BPAP transpulmonary utilization and A(max)/K(m) were reduced in WHHL (1.69 ± 0.16 vs, 2.9 ± 0.44 and 599 ± 69vs. 987 ± 153 ml/min in WHHL and control rabbits, respectively; P < 0.05 for both). No differences were observed in the AMP parameters. BPAP K(m) and A(max) values were estimated separately under mixed-order reaction conditions. No differences in K(m) values were found (9.79 ± 1 vs. 9.9 ± 1.31 μM), whereas WHHL rabbit A(max) was significantly decreased (5.29 ± 0.88 vs. 7.93 ± 0.8 μmol/min in WHHL and control rabbits, respectively; P < 0.05). We conclude that the observed pulmonary endothelial ACE activity reduction in WHHL rabbits appears related to a decrease in enzyme mass rather than to alterations in enzyme affinity.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume278
Issue number6 22-6
StatePublished - Jun 1 2000

Fingerprint

Peptidyl-Dipeptidase A
Rabbits
Lung
Adenosine Monophosphate
Enzymes
5'-Nucleotidase
New Zealand
Thorax
benzoylphenylalanyl-alanyl-proline

Keywords

  • 5'-nucleotidase
  • Endothelium
  • Pulmonary circulation
  • Watanabe heritable hyperlipidemic

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

Cite this

Reduced lung endothelial angiotensin-converting enzyme activity in Watanabe hyperlipidemic rabbits in vivo. / Orfanos, Stylianos E.; Parkerson, James B.; Chen, Xilin; Fisher, Lyle E; Glynos, Constantinos; Papapetropoulos, Andreas; Gerrity, Ross G.; Catravas, John D.

In: American Journal of Physiology - Lung Cellular and Molecular Physiology, Vol. 278, No. 6 22-6, 01.06.2000.

Research output: Contribution to journalArticle

Orfanos, SE, Parkerson, JB, Chen, X, Fisher, LE, Glynos, C, Papapetropoulos, A, Gerrity, RG & Catravas, JD 2000, 'Reduced lung endothelial angiotensin-converting enzyme activity in Watanabe hyperlipidemic rabbits in vivo', American Journal of Physiology - Lung Cellular and Molecular Physiology, vol. 278, no. 6 22-6.
Orfanos, Stylianos E. ; Parkerson, James B. ; Chen, Xilin ; Fisher, Lyle E ; Glynos, Constantinos ; Papapetropoulos, Andreas ; Gerrity, Ross G. ; Catravas, John D. / Reduced lung endothelial angiotensin-converting enzyme activity in Watanabe hyperlipidemic rabbits in vivo. In: American Journal of Physiology - Lung Cellular and Molecular Physiology. 2000 ; Vol. 278, No. 6 22-6.
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AU - Chen, Xilin

AU - Fisher, Lyle E

AU - Glynos, Constantinos

AU - Papapetropoulos, Andreas

AU - Gerrity, Ross G.

AU - Catravas, John D.

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