Characterization of beta-adrenergic receptors and adenylate cyclase activity in rat brown fat

Conference · Fri Feb 28 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5271648

Baresi, L A; Morley, J E; Scarpace, P J

Catecholamines stimulate thermogenesis in rat brown fat through a mechanism which involves binding to the beta-adrenergic receptor (BAR), stimulation of adenylate cyclase (AC) and culminating with uncoupling of mitochondrial respiration from ATP synthesis. The authors characterized BAR, AC and cytochrome (cyt) c oxidase in CDF (F-344) interscapular brown fat. Scatchard analysis of (/sup 125/)Iodopindolol binding yields a straight line consistent with a single class of antagonist binding sites with 41.8 +/- 12.0 fmol BAR/mg protein and a K/sub d/ of 118 +/- 15 pM. Binding was both specific and stereospecific. Competition with 1-propranolol (K/sub d/ = 6.7 nM) was 15 times more potent than d-propranolol (K/sub d/ = 103 nM). Competition with isoproterenol (K/sub d/ = 79 nM) was 10 times more potent than epinephrine (K/sub d/ = 820 nM) which was 35 times more potent than norepinephrine (K/sub d/ = 2.9 x 10/sup -5/ M) suggesting predominate beta/sub 2/-type BAR. Cyt c oxidase activity was assessed in brown fat mitochrondrial preparations. The ratio of BAR to cyt c activity was 959 +/- 275 nmol BAR/mol cyc c/min. Isoproterenol (0.1 mM) stimulated AC activity was 24 times GTP (0.1 mM) stimulated AC (98.5 vs 40.7 pmol cAMP/min/mg). NaF-stimulated AC was nine times basal activity (90.5 vs 11.3 pmol cAMP/min/mg). These data demonstrate the presence of a beta-/sub 2/-type BAR coupled to adenylate cyclase in rat brown fat.

• Research Organization: Sepulveda VA Medical Center, CA
• OSTI ID: 5271648
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:3; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADIPOSE TISSUE
ADRENAL HORMONES
ADRENALINE
AMINES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATECHOLAMINES
CELL CONSTITUENTS
CHEMISTRY
CONNECTIVE TISSUE
CONNECTIVE TISSUE CELLS
CYCLASES
CYTOCHROME OXIDASE
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYME ACTIVITY
ENZYMES
FAT CELLS
HAEM DEHYDROGENASES
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LYASES
MAMMALS
MEMBRANE PROTEINS
MITOCHONDRIA
NEUROREGULATORS
NORADRENALINE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
OXIDOREDUCTASES
PHENOLS
POLYPHENOLS
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SOMATIC CELLS
STEROID HORMONES
SYMPATHOMIMETICS
TISSUES
TRACER TECHNIQUES
VERTEBRATES