Dependence of beta-adrenergic responsiveness on thyroid state of male rats

• Published in: Clinical and experimental pharmacology & physiology Vol. 10; no. 2; p. 101
• Main Authors: Threatte, R M, Barney, C C, Baker, S P, Fregly, M J
• Format: Journal Article
• Language: English
• Published: Australia 01-04-1983
• Subjects: Animals; Heart Rate - drug effects; Isoproterenol - pharmacology; Kinetics; Male; Oxygen Consumption - drug effects; Rats; Rats, Inbred Strains; Receptors, Adrenergic - physiology; Receptors, Adrenergic, beta - physiology; Thyroid Gland - physiology; Thyroid Hormones - blood; Thyroidectomy; Thyroxine - blood; Triiodothyronine - blood
• ISSN: 0305-1870
• DOI: 10.1111/j.1440-1681.1983.tb00176.x

The dose of thyroxine (0-150 micrograms/kg body weight) administered subcutaneously daily to surgically thyroidectomized male rats was correlated significantly with their metabolic activity as assessed by rate of oxygen consumption and colonic temperature. There was a significant dose-dependent increase in total serum thyroxine, triiodothyronine and reverse-triiodothyronine concentrations with increasing doses of thyroxine administered. The cardiostimulatory response to administration of isoprenaline (8 micrograms/kg body weight s.c.) was also correlated directly with the dose of thyroxine administered. The concentration of cardiac beta-adrenoceptors in these animals was correlated significantly with total serum thyroxine and triiodothyronine concentrations, basal heart rate, and the chronotropic response to administration of isoprenaline.