Effects of altered ventilatory patterns of rabbit pulmonary endothelial angiotensin converting enzyme function, in vivo

Conference · Sat Mar 01 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5389429

Toivonen, H J; Catravas, J D

Because alveolar pressure can influence pulmonary blood flow, volume and surface area, the authors have studied the effects of airway pressure on endothelial angiotensin converting enzyme (ACE) function in rabbit lungs in vivo, utilizing indicator dilution techniques with /sup 3/H-Benzoyl-Phe-Ala-Pro (BPAP) as substate. Static inclation of the lungs to a pressure of 0 or 5 mmHg did not change percent transpulmonary metabolism and Amax/Km ratio in comparison to control measurements during conventional mechanical ventilation. When the inflation pressure was increased to 10 mmHg, percent metabolism of /sup 3/H-BPAP remained unaltered but Amax/Km decreased over 40% from control. This decrease was in close relation to the reduction in pulmonary blood flow. Addition of 5 cm H/sub 2/O positive end-expiratory pressure (PEEP) to the mechanical ventilation also decreased Amax/Km values and pulmonary blood flow but did not influence percent metabolism of /sup 3/H-BPAP. These results suggest that the detected alterations in ACE kinetics were more likely due to hemodynamic changes than enzyme dysfunction. The authors propose that high static alveolar pressures as well as PEEP did not affect angiotensin converting enzyme function, but reduced the fraction of perfused microvessels reflected in changes in Amax/Km ratios.

• Research Organization: Medical College of Georgia, Augusta
• OSTI ID: 5389429
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANGIOTENSIN
ANIMAL TISSUES
ANIMALS
BIOLOGICAL FUNCTIONS
BLOOD FLOW
BODY
CARDIOVASCULAR AGENTS
DRUGS
ENDOTHELIUM
ENZYMES
FUNCTIONS
GLOBULINS
IN VIVO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LUNGS
MAMMALS
METABOLISM
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RABBITS
RESPIRATORY SYSTEM
SUBSTRATES
SURFACE AREA
SURFACE PROPERTIES
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VASOCONSTRICTORS
VERTEBRATES