Glial high-affinity binding site with specificity for angiotensin II not angiotensin III: a possible N-terminal-specific converting enzyme

Journal Article · Wed Jan 01 00:00:00 EST 1986 · J. Cardiovasc. Pharmacol.; (United States)

DOI:https://doi.org/10.1097/00005344-198600101-00013· OSTI ID:6478199

Printz, M P; Jennings, C; Healy, D P; Kalter, V

Anomalous binding properties of angiotensin II to fetal rat brain primary cultures suggested a possible contribution from contaminating glia. To investigate this possibility, cultures of C6 glioma, a clonal rat cell line, were examined for the presence of angiotensin II receptors. A specific high-affinity site for (/sup 125/I)angiotensin II was measured both by traditional methodology using whole cells and by autoradiography. This site shared properties similar to that found with the brain cells, namely low ligand internalization and markedly decreased affinity for N-terminal sarcosine or arginine-angiotensin analogs. The competition rank order was angiotensin II much greater than (Sar1,Ile8)angiotensin II greater than or equal to des(Asp1,Arg2)angiotensin II. Angiotensin III did not compete for binding to the site. High-pressure liquid chromatography analysis indicated that the ligand either in the incubation or bound to the site was stable at 15 degrees C, but there was very rapid and extensive degradation by the C6 glioma cells at 37 degrees C. It is concluded that the site exhibits unusual N-terminal specificity for angiotensin with nanomolar affinity for angiotensin II. If angiotensin III is an active ligand in the brain, the site may have a converting enzyme function. Alternatively, it may form the des-Asp derivatives of angiotensin for subsequent degradation by other enzymatic pathways. Either way, it is proposed that the site may modulate the brain-angiotensin system.

• Research Organization: Univ. of California, San Diego, La Jolla
• OSTI ID: 6478199
• Journal Information: J. Cardiovasc. Pharmacol.; (United States), Journal Name: J. Cardiovasc. Pharmacol.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ANGIOTENSIN
BIOCHEMICAL REACTION KINETICS
RECEPTORS
AFFINITY
AUTORADIOGRAPHY
BRAIN
GLIOMAS
IODINE 125
LIGANDS
LIQUID COLUMN CHROMATOGRAPHY
RATS
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
NEOPLASMS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SEPARATION PROCESSES
VASOCONSTRICTORS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques