Role of. beta. -adrenoceptors in thyroxine-induced hypertrophy

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

OSTI ID:7189480

Eliades, D; Weiss, H R

The role of ..beta..-adrenoceptors in the development of thyroxine (T/sub 4/)-induced hypertrophy was studied in New Zealand white rabbits. Radiolabelled microspheres were used to measure coronary blood flow, and (/sup 125/I)-pindolol was used for Scatchard analysis of cardiac membranes to determine ..beta..-adrenoceptor density (B/sub max/) and affinity. After 16 d of T/sub 4/, coronary blood flow (CBF) was elevated from 257 +/- 31 ml/min/100 g (mean +/- SD) to 530 +/- 152 and B/sub max/ increased from 24.0 +/- 6.2 fmol/mg membrane protein to 47.3 +/- 12.0. Heart weight (HW) was elevated 30%, and heart weight/body weight (HW/BW) increased 70% above control. T/sub 4/ + propranolol (9 mg/kg/d) diminished CBF from levels seen with T/sub 4/ alone, to 361 +/- 146 ml/min/100g. However B/sub max/ elevations were unchanged from values with T/sub 4/. HW and HW/BW increases were insignificantly less than with T/sub 4/ alone. CBF in T/sub 4/ + pindolol (0.9 mg/kg/d) animals was similar to that with T/sub 4/ alone, but B/sub max/ increases were prevented (32.0 +/- 11.0). HW and HW/BW were both lower than with T/sub 4/ alone (153% of control). Thus, it appears that pindolol is more able to reverse some of the effects of T/sub 4/ than is propranolol, possibly due to prevention of ..beta..-adrenoceptor upregulation as a result of its intrinsic sympathomimetic ability.

• Research Organization: UMDNJ-Rutgers Medical School, Piscataway
• OSTI ID: 7189480
• 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
AFFINITY
AMINO ACIDS
ANIMALS
ARTERIES
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BLOOD FLOW
BLOOD VESSELS
BODY
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CELL MEMBRANES
CORONARIES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HEART
HORMONES
HYPERTROPHY
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MICROSPHERES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
PATHOLOGICAL CHANGES
PEPTIDE HORMONES
PROTEINS
RABBITS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SYMPATHOMIMETICS
THYROID HORMONES
THYROXINE
TRACER TECHNIQUES
VERTEBRATES