[The effect of fluoridated phenylethanolamines on hyperglycemia induced by catecholamines in the rat]

10 compounds from the 2.4- and 3.4-difluorinated phenylethanol-amines series were tested for their antagonistic action against a hyperglycemia induced by catecholamines in rats, and the ED50 and AD50 values were determined. All the substances acted beta-adrenolytically, with the glycogenolysis enhanced by isoproterenol being blocked more potently by 3.4-difluorophenylethanolamines than by the corresponding 2.4-difluoroderivatives. An exception in the series is 2.4-difluoro-n-butylnoradrenalin, which acts 10fold more beta-adrenolytically than the 3.4-difluoroderivative, and has 3 times the effect of the comparative substance dichloroisoproterenol.