Effects of beta-adrenoceptor agonists and antagonists on thyroid hormone secretion.
The effects of various beta-adrenoceptor agents on radioiodine release from the thyroid were studied in mice pretreated with 125I and thyroxine. The non-selective beta-adrenoceptor agonist isopropylnoradrenaline and the selective beta 2-adrenoceptor agonist terbutaline both, and with the same efficacy, enhanced radioiodine release, whereas the selective beta 1-adrenoceptor agonist prenalterol had no such effect. The non-selective beta-adrenoceptor antagonist L-propranolol and the selective beta 2-adrenoceptor antagonist ICI 118,551 both abolished the radioiodine release induced by isopropylnoradrenaline or by terbutaline. The selective beta 1-adrenoceptor antagonist metoprolol inhibited the radioiodine response to isopropylnoradrenaline, but not that to terbutaline. Neither of the beta-adrenoceptor antagonists influenced the radioiodine release induced by TSH. It is concluded that the beta-adrenoceptors involved in the regulation of thyroid hormone secretion are mainly of the beta 2-subtype, and, further, that beta-adrenoceptor agonists and TSH exert their thyroid hormone secretory effects through different mechanisms.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D005260:Female; D007457:Iodine Radioisotopes; D051379:Mice; D008815:Mice, Inbred Strains; D011941:Receptors, Adrenergic / Q000494:pharmacology*; D011943:Receptors, Adrenergic, beta / Q000494:pharmacology*; D013726:Terbutaline / Q000494:pharmacology; D013963:Thyroid Hormones / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D007457:Iodine Radioisotopes; D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D013963:Thyroid Hormones; D013972:Thyrotropin; D013726:Terbutaline