Binding of the angiotensin-converting enzyme inhibitor, RACX-65, to trout gills

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

OSTI ID:5417430

Olson, K R; Evan, A P; Ryan, J W

Galardy et al. have shown that in rainbow trout, Salmo gairdneri, nearly all of the angiotensin converting enzyme (ACE) activity is found in the gills. In the present study, binding and localization of the angiotensin-converting enzyme inhibitor N-(1(S)-carboxanili-dopropyl)-L-Ala-L-Pro (RAC-X-65) to trout gill was examined in homogenized gill tissues, an isolated perfused gill and by autoradiography. RAC-X-65 inhibited gill ACE as effectively as it inhibits human ACE; the apparent Ki for gill homogenates fell over 15 min from 3 x 10/sup -9/M to 5.5 x 10/sup -10/M. In the arterioarterial pathway (supplying the systematic circulation) of the perfused gill, /sup 3/H-RAC-X-65 extraction (compared to the inert volume maker, /sup 14/C-sucrose) decreased from 72.2 +/- 4.5% after 6 min perfusion to 54.7 +/- 6.8% (14 min) and 38.4 +/- 9.0% after 20 min (N = 6). By 40 min, extraction was less then 10% indicating saturation of ACE binding sites. Relatively little extraction was observed in the gill arteriovenous pathway. Autoradiography of gills perfused with /sup 3/H-RAC-X-65 demonstrated that the pillar cells are the major site of /sup 3/H accumulation and, therefore, probably contain most of the ACE activity.

• Research Organization: Indiana Univ., Notre Dame
• OSTI ID: 5417430
• 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

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANGIOTENSIN
ANIMAL TISSUES
ANIMALS
AQUATIC ORGANISMS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BIOLOGICAL PATHWAYS
BODY
CARDIOVASCULAR AGENTS
DRUGS
ENZYME ACTIVITY
ENZYME INHIBITORS
FISHES
GILLS
GLOBULINS
KINETICS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
ORGANIC COMPOUNDS
PERFUSED TISSUES
PROTEINS
REACTION KINETICS
RECEPTORS
RESPIRATORY SYSTEM
TISSUES
TRITIUM COMPOUNDS
TROUT
VASOCONSTRICTORS
VERTEBRATES