Role of beta adrenoceptors in the hypertrophic response to thyroxine

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Journal of Cardiovascular Pharmacology; (USA)

DOI:https://doi.org/10.1097/00005344-198907000-00011· OSTI ID:5364489

Eliades, D; Weiss, H R ^[1]

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1. Univ. of Medicine and Dentistry of New Jersey, Piscataway (USA)

The ability of beta-adrenoceptor blockade to reduce the hypertrophic response to thyroxine (T4, 0.5 mg/kg per day, s.c.) was tested in New Zealand white rabbits. Two beta-adrenergic blocking agents, one a full antagonist (propranolol, 9.6 mg/kg per day) and the other a partial agonist (pindolol, 0.96 mg/kg per day) were administered in combination with T4 in an effort to reduce myocardial hypertrophy. A 3 and 16 day group were generated to test the time course of the hypertrophic and receptor responses. Coronary blood flow was measured using radioactive microspheres, and beta-adrenoceptor number and affinity were measured using 125I(-) pindolol as the radioligand. T4 increased coronary blood flow to 1.95 times control values in the 3 day group and 2.2 times control levels in the 16 day group; beta-adrenoceptor number was increased similarly in 3 and 16 day groups to 1.9 times control Bmax levels. Heart weight (HW) to body weight (BW) ratios were significantly increased in only the 16 day group to 1.22 and 1.61 times control, respectively. Treatment with propranolol + T4 blunted the coronary blood flow increase, but receptor upregulation occurred to the same extent as with either substance alone. The HW/BW was increased to 1.49 times control. Pindolol + T4 did not decrease coronary blood flow but blocked beta-adrenoceptor upregulation. The HW was reduced to control levels and the HW/BW ratio was 1.40 times control and significantly decreased from T4 alone. Thus, pindolol was effective in reducing the hypertrophic response to T4, whereas propranolol was only moderately effective in doing so.

• OSTI ID: 5364489
• Journal Information: Journal of Cardiovascular Pharmacology; (USA), Journal Name: Journal of Cardiovascular Pharmacology; (USA) Vol. 14:1; ISSN 0160-2446; ISSN JCPCD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
ARTERIES
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL FUNCTIONS
BLOOD FLOW
BLOOD PRESSURE
BLOOD VESSELS
BODY
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
CORONARIES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
FUNCTIONS
HEART
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MICROSPHERES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
PEPTIDE HORMONES
PROTEINS
RABBITS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SYMPATHOLYTICS
SYMPATHOMIMETICS
THYROID HORMONES
THYROXINE
TRACER TECHNIQUES
VERTEBRATES