Effect of the beta-adrenergic substances propranolol, alprenolol and isoprenaline on cAMP production in bovine thyroid slices.

The effect of the beta-adrenergic blockers L-alprenolol and DL-propranolol and of the beta-adrenergic agonist L-isoprenaline on the basal and thyrotropic hormone(TSH)-stimulated cyclic adenosine-monophosphate (cAMP) level in bovine thyroid slices was studied. The main basal cAMP level in bovine thyroid slices was 3 pmol/mg tissue. TSH stimulated cAMP production in correlation to the concentration. Maximum stimulation was achieved with a TSH concentration of 10 mU/ml. The beta-blockers DL-propranolol and L-alprenolol caused 74 and 77% inhibition of TSH-stimulated cAMP synthesis respectively. The beta-adrenergic agonist L-isoprenaline did not significantly affect either the basal or the TSH-stimulated cAMP level. The role of the beta-adrenergic receptor system in the regulation of TSH-stimulated cAMP synthesis is discussed.