Dopamine agonist-induced hyperglycemia in rats: effects of lergotrile mesylate

Lergotrile and apomorphine, two direct-acting dopamine agonists, caused marked hyperglycemia in fasted rats, while compounds which release endogenous dopamine (amphetamine, methylphenidate) or inhibit dopamine reuptake (LR5182), failed to elevate blood glucose. The effect of lergotrile was dose dependent, causing blood glucose to rise 3-fold above resting levels at 5 mg/kg (i.p.). Blood glucose increased prior to the onset of the behavioral signs of dopamine stimulation. The effect of lergotrile was attenuated by phentolamine, propranolol or butaclamol. Adrenalectomy also prevented lergotrile-induced hyperglycemia. These data indicate that hyperglycemia is not a property of all compounds that cause dopaminergic effects. The action of lergotrile might be indirect, perhaps mediated through release of catecholamines from the adrenal glands.