EFFECT OF CERTAIN ANTIHISTAMINICS ON EPINEPHRINE-INDUCED HYPERGLYCEMIA AND LACTICACIDEMIA

¹ Department of Physiology, Boston University School of Medicine, Boston, Massachusetts

Although a majority of adrenergic blocking drugs have been shown to diminish epinephrine-induced hyperglycemia in rabbits, it has been observed that potent antihistaminics and several pressor agents are likewise effective. A number of the available synthetic antihistaminics have been tested for their effects on epinephrine-induced hyperglycemia and lacticacidemia in dogs. It was found that those compounds which have been shown to be the most potent in antagonizing the effects of histamine on the bronchioles and intestines of guinea pigs, are also the most effective in reducing the epinephrine hyperglycemia in rabbits, presumably because of reduced hepatic glycogenolysis. The effectiveness of the antihistaminic agents is not related to their ethylenediamine structure, their atropine-like, or local anesthetic activity. Pressor agents such as Pitocin, Pitressin, and ephedrine diminished the induced hyperglycemia. The evidence suggests that antihistaminics inhibit epinephrine hyperglycemia more readily in the rabbit than in the dog which may reveal an important species difference. None of the adrenergic blocking drugs and antihistaminics tested in dogs decreased epinephrine induced lacticacidemia, thus suggesting that the rate of muscle glycogenolysis was not affected by the drugs. There is, on the other hand, some indication that the rate of utilization of blood sugar is increased by adrenergic blocking drugs.