Relative lipolytic activities of selected catecholamines in the mouse

The adipokinetic activities, relative to isoproterenol as 1,000, in sedated, phenoxybenzamine pretreated unfasted mice were: norepinephrine 540, epinephrine 330, N-t-butylnorepinephrine 130, isoetharine 30 and N-cyclopentylbutanefrine 10. These relative activities correlate (r=0.88) with the medians of some previously defined beta1-adrenoceptor activities, but not (r=less than 0.1) with the medians of some previously defined beta2-adrenoceptor activities. These findings are in accord with the previously suggested view that an alpha, beta1-, beta2-, adrenoceptor concept is in better accord with experimental evidence that is an alpha- and beta-adrenoceptor one.