Effects of a new selective beta1-adrenoceptor agonist on amylase secretion from the rat parotid gland

The effects of a new selective beta1-adrenoceptor agonist, (--)-1-(4-hydroxyphenoxy)-3-isopropyl-amino-propanol-2-hydrochloride (H 133/22), on amylase secretion from the rat parotid gland were investigated in an in vitro system. The results were compared to the secretory responses obtained with noradrenaline, adrenaline, methoxyamine and terbutaline. H 133/22 was found to be a potent enzyme secretagogue and appeared even more effective than noradrenaline and adrenaline, particularly at low concentrations. The beta1-adrenoceptor agonist, terbutaline, also stimulated amylase discharge from the parotid gland but was much less potent than H 133/22. Methoxyamine had no effect on enzyme secretion. We suggest that the adrenergic stimulation of amylase secretion from the rat parotid gland is mainly mediated by beta1-receptors.