Identification of beta-adrenergic receptors on cultured human fibroblast IMR-90 cells

Conference · Wed Mar 05 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6991754

Scarpace, P J

Fibroblast cultures derived from normal human tissue undergo a finite number of population doublings when serial subcultivated in vitro. IMR-90 cells derived from human embryonic lung tissue undergo approximately 60 population doublings. Beta-adrenergic receptor (BAR) characteristics and isoproterenol-stimulated adenylate cyclase activity were assessed in IMR-90 cells at various population doublings (PDL). Scatchard analysis of /sup 125/I-Iodocyanopindolol (ICYP) binding yields a straight line consistent with a single class of antagonist binding sites with 452 +/- 35 sites/cell and a dissociation constant of 18.7 +/- 1.3 pM. There were no changes in BAR density between PDL 32 to PDL 46. Binding was both stereospecific and specific. Competition with epinephrine was 7.4 times more potent than with norepinephrine, suggesting predominate beta/sub 2/-type BAR. Competition with isoproterenol (Hill plots) indicated an apparent K/sub d/ of 1.3 +/- 0.1 x 10/sup -8/ M. Competition curves were resolved into high and low affinity binding sites yielding K/sub d/-high = 3.6 +/- 1.3 nM and k/sub d/-low = 1.6 +/- 0.7 x 10/sup -7/ M with 49.9 +/- 6.6% of the receptors in the high affinity state at PDL 31 to PDL 37. Cultures demonstrate isoproterenol-stimulated adenylate cyclase activity with a concentration of 1 x 10/sup -6/ M producing half-maximal stimulation and a maximum stimulation of 2 pmol cAMP/mg/min. Forskolin-stimulated was 10 pmol/cAMP/mg/min at PDL 46.

• Research Organization: Sepulveda VA Medical Center, CA
• OSTI ID: 6991754
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:4
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ADRENALINE
AFFINITY
ANIMAL CELLS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CULTURES
CONNECTIVE TISSUE CELLS
CYCLASES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYME ACTIVITY
ENZYMES
FIBROBLASTS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LYASES
MAMMALS
MAN
MEMBRANE PROTEINS
NEUROREGULATORS
NORADRENALINE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SOMATIC CELLS
STEROID HORMONES
SYMPATHOMIMETICS
TRACER TECHNIQUES
VERTEBRATES