Metabolic effect of alpha-and the beta-adrenergic stimulation of rat submaxillary gland in vitro.

1. Incubation of submaxillary-gland slices with isoproterenol, a beta-adrenergic agonist, stimulated glucose removal by 41% and decreased tissue [glucose 6-phosphate] by 50%. Propranolol blocked these effects of isoproterenol. 2. Phenylephrine, an alpha-adrenergic agonist, stimulated glucose removal by 35% and decreased tissue [glucose 6-phosphate] by 75%. In addition, phenylephrine also completely overcame the inhibition of pyruvate removal caused by acetoacetate metabolism and decreased tissue [atp] by 45%. Phentolamine blocked the effects of phenylephrine. 3. In contrast with beta-adrenergic stimulation, alpha-adrenergic stimulation required exogenous Ca2+. 4. These results explain the different metabolic responses of the submaxillary gland to adrenaline in the presence and absence of exogenous Ca2+.